Human Biology [Bio 156]

May 10, 2012

Unit 4 Lab

Filed under: Uncategorized — brewoods90 @ 2:33 am

Unit 4 Lab

In this lab we were ins
tructed to do research on one of the many biodiversity hotspots that are found in this world. Learning about hotspots is important because they show us just how many plants and animals are really affected by humans and by natural causes throughout the world.


There are many different things that are factored into determining whether or not a certain region is considered a biodiversity hotspot, these include the amount of endemic (native) plant/animal species they have, and how much of their levels of habitat loss.

Japan is a country that consists of over 3,000 islands that stretch from the subtropics to the boreal zone (it is located in the Pacific Ocean and stretches from off the coast of S. Korea north to off the coast of Russia). There are many types of ecosystems that are found in Japan, these include mountainous (which surprisingly makes up about 73% of its terrain).
One of the endemic animal species found in Japan is the Bonin Flying Fox (a type of fruit bat). This bat is on the brink of extinction because they are unable to find food or a roosting place due to disappearing forests in this country. One of the endemic plant species found in Japan is the Pteridophyllum racemossum; which is a flowering plant that is a part of the poppy family.

(Bonin Flying Fox)

(Pteridophyllum racemossum)

Japan is considered to be a hotspot because it has 1,950 endemic plant species (according to the website it needs to have over 1,500 in order to be considered a hotspot), as well as the fact that only 20% of the original vegetation remains intact in this country (according to the website it had to have lost at least 70% of it, and it has lost 80%).

Socio Economic Status of Japan: Signs of a boost in Japan’s economy can be seen in parts of Japan, but that is solely due to the external demand of their supplies; but domestic demand remains low and their job market still remains fairly tight. They are fairly tight on funds in their government, which in turn is lowering the amount of money they can invest into their technology and conservation of their plants/wildlife. They also have a declining birth-rate and an increasingly aging population, which isn’t giving them any incentive to boost their standards of living.

This country should probably start to become more concerned w/their species extinction (even though as of today only even though only about 40 of their endemic animals are considered “threatened” and 7 species are already extinct). Due to the fact that they are tearing down more forests (to build ski resorts, golf courses, roads, etc.) they are removing many of these animals’ homes and sources of nourishment. Not to mention due to deforestation they are removing their endemic plants as well.

One of the “threatened” species that is endemic to Japan is the Amami rabbit. In order to help protect this species (as well as other endangered and threatened species of the country) Japan has opened 28 national parks. They have also become a part of the Critical Ecosystem Partnership Fund which helps to provide funding to the biodiversity hot spots around the world in order for them to be able to protect their environment.

(Amami Rabbit)

I personally believe that it is important for people to be worried about the loss of biodiversity hotspots around the world. Although it may not have a huge impact on us in our daily lives it could have a large impact on our earth’s atmosphere, What with the new movement away from ruralization to urbanization due to population growths it has put many more pollutants into our air, soil and water. We should be trying to maintain what little untouched land we have left in order to try to preserve the atmosphere of our Earth.

This lab has taught me many different things about Japan. I had never known that it was considered to be a hotspot before this lab; I also never knew that it had so many endemic plant and animal species. People need to realize that it is crucial for the future of our planet for people to conserve our nations land, plants, and animals. If we keep taking advantage of our nature then eventually it will have even more harmful effects on our atmosphere that could be irreversible.

May 9, 2012

Unit 4 compilation

Filed under: Uncategorized — brewoods90 @ 12:58 am

Unit 4 Compilation
Table Of Contents
Chapter 14:-Digestive system brings nutrient into body
-Mouth Processes food for swallowing
-Pharynx & esophagus deliver food to stomach
-Stomach stores food, digests protein & regulates delivery
-Small intestine digests food & absorbs nutrients & water
-Accessory organs aid digestion & absorption
-Large intestine absorbs nutrients & eliminates wastes
-How nutrients are absorbed
-Endocrine & nervous system regulate digestion
-Nutrition: you are what you eat
-weight control: energy consumed vs. energy spent
-Disorders of digestive tract
-Eating Disorders

Chapter 11
-4 characteristics of nervous system
-Nervous system has 2 principal parts
-Neurons are communication cells
-Neurons initiate action potentials
-Neuroglial cells support/protect neurons
-Info is transferred from neuron to its target

Chapter 12
-Receptors receive and convert stimuli
-Somatic sensations arise from receptors throughout body
-Vision: detecting & interpreting stimuli
-Disorders of sensory mechanisms

Chapter 24
-Pollutants impact air quality
-Pollution jeopardizes scarce water supplies
-Pollution & overuse damage land

Global Warming in News Today

Chapter 14: Digestive System and Nutrition
Nutrients are substances in food that are required for growth reproduction and the maintenance of health.

*Digestive System Brings Nutrients into the Body
Digestive System consists of all the organs that share the common function of getting nutrients into the body.It is made up of the gastrointestinal tract, which is a hollow tube that extends from mouth to anus- it includes the: mouth, pharynx, esophagus, stomach, small intestine, large intestine, rectum, and anus.
It also includes 4 accessory organs: the salivary glands, liver, gallbladder and pancreas.
Walls of GI tract are composed of 4 layers:
1-Mucosa: innermost layer of tissue, all nutrients must cross this to enter blood.
2-Submucosa: layer of connective tissue that contains blood vessels, lymph vessels and nerves.
3-Muscularis: responsible for motility, consists of 2 or 3 sub layers of smooth muscle.
4-Serosa: thin connective tissue sheath, surrounds and protects the other 3 layers and attaches digestive system to walls of body cavities.
*5 Basic Processes accomplish digestive system function
1-Mechanical processing and movement- Chewing breaks food into smaller pieces and 2 types of movement mix the contents of the lumen and propel it forward.
2-Secretion-Flud, digestive enzymes, acid, alkali, bile, and mucus are all secreted into GI tract at various places.
3-Digestion-Contents of the lumen are broken down both mechanically and chemically into smaller particles, culminating in nutrient molecules
4-Absorption-Nutrient molecules pass across the mucosal layer of GI tract into blood/lymph.
5-Elminination-Undigested material is eliminated from the body via the anus.

*2 Types of motility aid in digestive processes
Peristalsis-propels food forward; this begins when a lump of food (bolus) stretches a portion of the GI tract, causing smooth muscle in front of the bolus to relax and the muscle behind it to contract. The contractions push the food forward, stretching the next part of the tube and causing muscle relaxation in front and contraction behind. The peristaltic wave of contractions helps to mix the contents of the stomach and push the contents of the esophagus/intestines forward.
Segmentation- mixes good- short sections of smooth muscle contract/relax in a random fashion. Result of this is a back and forth mixing of contents of the lumen. Food particles are pressed against the mucosa, enabling the body to absorb their nutrients. This type of movement occurs primarily in the small intestine as food is digested/absorbed.

*The Mouth processes food for swallowing
**Teeth Bite and Chew Food
Teeth chew food into pieces small enough to swallow. There are 4 types of teeth, each with a specialized purpose: Incisors cut food, and the canines tear it, pre-molars/molars grind and crush food. Children have only 20 teeth, but adults have 32 permanent teeth.

**Tongue positions and tastes food
The tongue helps to position food over teeth and mash it against the roof of the mouth. The tongue consists of a skeletal muscle enclosed in mucous membrane.

**Saliva begins the process of digestion
3 pairs of salivary glands produce fluid called saliva. The parotid gland lies near the back of the jaw, and the sublingual and submandibular glands are located just below the lower jaw and below the tongue. Saliva moistens food making it easier to chew and swallow.
4 ingredients of mucous include: Mucin- which is a mucus-like protein that holds food particles together so they can be swallowed more easily; Salivary amylase- begins the process of digesting carbs; Bicarbonate- maintains the pH of the mouth between 6.5-7.5; Lysozyme- inhibits bacterial growth.

( 4/21/2012)

*Pharynx and Esophagus deliver food to the stomach
After we have chewed our food and mixed it w/saliva, the tongue pushes it into the pharynx (throat) for swallowing. The presence of food in the pharynx stimulates receptors and initiates the “swallowing reflex”. The soft palate rises to close off the passageway into the nasal cavity and the larynx rises slightly. The epiglottis bends to close the airway to the trachea temporarily, so we do not inhale the food
Esophagus- muscular tube consisting of both skeletal and smooth muscle that connects the pharynx to the stomach; its lining produces lubricating mucus that helps food to slide more easily. The lower esophageal sphincter, located at the base of the esophagus opens briefly as food arrives and closes after it passes into the stomach. This sphincter prevents reflux of the stomach’s contents back into the esophagus.

*Stomach stores food, digests protein and regulates delivery
Stomach= a muscular, expandable sac that performs the following functions
1-Food Storage- the stomach stores food until it can be digested and absorbed. The stomach shrinks when empty, then expands to 1-3 liters of capacity when we eat.
2-Digestion- It digests proteins using strong acid protein-digesting enzymes. This acid also kills most bacteria. Muscle contractions mix these secretions w/food, assist in mechanically breaking apart food, and push the mixture into the small intestine.
3- Regulation of delivery- Stomach regulates the rate at which food is delivered into the small intestine.

Gastric Juice breaks down proteins
In the mucosal layer there are millions of small openings called gastric pits that lead to gastric glands below the surface. Most of these cells secrete pepsinogen, which is a large precursor molecule that becomes a protein-digesting enzyme called pepsin.
Stomach typically produces 1-2 liters of gastric juice (pepsin mixed w/HC1) per day. The acid gives the stomach an acidic pH of approximately 2. Pepsin and acid in gastric juice dissolve the connective tissue in food and digest proteins and peptides into amino acids so they can be absorbed into the small intestine. Chyme= watery mixture of partially digested food and gastric juice that is delivered to the small intestine
Stomach contractions mix food and push it forward
While your stomach is empty, muscle contractions keep it small. When you eat, contractions cease and the stomach relaxes and stretches to accommodate the food. Stretching signals peristalsis to increase. Each wave of peristalsis starts at the lower esophageal sphincter and moves toward the pyloric sphincter, becoming stronger as it proceeds. Peristaltic wave pushes the chime forward, and when there is nowhere else for it to go, backward again in a squeezing, mixing motion. A peristaltic contraction occurs every 15-25 seconds. It takes 2-6 hours for a stomach to completely empty after a meal. Chyme w/ a high acid or fat content stimulates the release of hormones that slow stomach peristalsis, giving the small intestine more time to absorb the nutrients.
The stomach doesn’t absorb nutrients because it lacks the required cellular transporting mechanisms and because its inner lining is coated w/mucous.

*The small intestine digests food and absorbs nutrients and water
**Small intestine has 2 major functions:
1-Digestion- stomach partially digests proteins to smaller peptides; Protein digestion continues in the small intestine, and here we also digest carbs and lipids.
2-Absorption- Proteins, carbs, and lipids in foods are broken down to single amino acids, monosaccharide’s, fatty acids, and glycerol, which are small enough to be transported across mucosal cells into the blood. Nearly 90% of absorbable nutrients and water is absorbed in the small intestine.

Small intestine consists of 3 different regions: The duodenum is the first region, which is appx 10 inches long, this is where the most digestion occurs; the products of digestion are absorbed primarily in the other 2 segments the jejunum and the ileum, which together are 10 feet long.
The mucosa contains large folds covered with microscopic projections called villi; each epithelial cell of the villi has dozens of smaller, cytoplasmic projections called microvilli. Combined the villi and microvilli enlarge the surface area of the small intestine by more than 500 times.

*Accessory organs aid digestion and absorption
**Pancreas secretes enzymes and NaHCO3
Pancreas-elongated organ that lies just behind the stomach; it has both endocrine and exocrine functions. As an endocrine gland it secretes hormones that regulate blood glucose levels. In its exocrine role it produces and secretes digestive enzymes (which include proteases such as trypsin, chymotrypsin, and carboxypeptidase), pancreatic amylase (which continues digestion of carbs) and sodium bicarbonate (which functions to neutralize stomach acid). 2 pancreatic ducts deliver these secretions to the duodenum, where they facilitate process of digestion.

**The liver produces bile and performs many other functions
Liver is a large organ located in the upper right abdominal cavity. Liver’s primary digestive function is to facilitate the digestion and absorption of lipids by producing bile, which is a water mixture containing electrolytes, cholesterol, bile salts, lecithin, and pigments derived from breakdown of hemoglobin. Bile salts emulsify lipids in the small intestine; they break them into smaller droplets.
Hepatic portal system: carries nutrient-rich blood directly from the digestive organs to the liver via the hepatic portal vein. After passing through the liver, the blood is returned to the general circulation.

**Liver helps to maintain homeostasis by:
-Storing fat-soluble vitamins –storing glucose as glycogen after a meal, and converting glycogen to glucose between meals –Synthesizing and storing some lipids – Destroying worn-out red blood cells –Converting ammonia into less toxic urea
**Gallbladder stores bile until needed
Gallbladder concentrates bile by removing most of the water and stores it until after a meal, when it is secreted into the small intestine via the bile duct.

*Large intestine absorbs nutrients and eliminates wastes
The large intestine absorbs most of the remaining nutrients and water, and stores the now nearly solid waste material until it can be eliminated.

Most of the large intestine consists of 4 regions collectively known as the colon. The ascending colon rises along the right side of the body, the transverse colon crosses over to the left, and the descending colon passes down the left side to the sigmoid colon, which is where feces is stored until defecation.

( 4/21/2012)

*How nutrients are absorbed
**Proteins and carbs are absorbed by active transport
In the small intestine enzymes from the pancreas and enzymes secreted by the mucosal layer of the stomach and small intestine itself break down proteins into amino acid. The amino acids are then actively transported into the mucosal cells; eventually they move by facilitated diffusion out of those cells and make their way into capillaries.

**Lipids are broken down, then reassembled
The products of lipid digestion are fatty acids and monoglycerides; because they are non-polar these quickly dissolve in micelles (small droplets of bile and lechtin that have a polar outer surface and a non-polar inner core). Micelles primary functions are to transport fatty acids and monoglycerides to the outer surface of the mucosal cells so they can be absorbed into cells. Once inside the cells the fatty acids and monoglycerides recombine into triglycerides.

**Water is absorbed by osmosis
AS nutrients are absorbed in the small intestine, the concentration of the water in the intestinal lumen becomes higher than in the intestinal cells or in the blood. Higher concentration of water in the lumen represents a strong driving force for the diffusion of water through the epithelial layer of cells of the small intestine and into the blood.

**Vitamins and minerals follow a variety of paths
Fat-soluble vitamins dissolve in the micelles and are absorbed by diffusion across the lipid membrane of the mucosal cell layer. Water-soluble vitamins are absorbed either by active transport or diffusion through channels or pores. Minerals such as sodium, potassium, calcium, phosphate, sulfate and magnesium are electrically charged and hence not lipid soluble; thee are either actively transported or are absorbed by diffusion via specific transport proteins, pores, or channels.

*Endocrine and nervous systems regulate digestion
**Regulation depends on volume and content of blood
Endocrine system and nervous system regulate digestion according to both the volume and content of food. When stomach stretches to accommodate food, neutral reflexes increase stomach peristalsis and secretion of gastric juice. Stretching and presence of protein stimulate the stomach to release the hormone gastrin, which triggers the release of more gastric juice.
When chime arrives in the small intestine, stretching of the duodenum increases segmentation to mix the chime. The duodenum also secretes 2 hormones into the blood stream: secretin- stimulates the pancreas to secrete water and bicarbonate to neutralize acid, cholecystokinin (CCK) – signals the pancreas to secrete more digestive enzymes.
Secretin, CCK, and stretching of the small intestine inhibit stomach motility and stomach secretion; so if chime flows too quickly from the stomach the small intestine will slow stomach activity accordingly.
**Nutrients are used or stored until needed
Regulation of organic metabolism involves interactions between virtually all the organs in the body. Key organs are the pancreas (which secretes insulin and glucagon) and the liver. Lipids, carbs, and proteins can all be converted to storage forms of lipid or carbs, and then recycled according to the body’s needs. When we consume more energy-containing nutrients than we use, our bodies store the excess for future use; over time, these reserves can increase body weight. When we consume fewer energy-containing nutrients than we use, the body draws on these storage forms of energy to make up the difference; if we do this on a regular basis, we lose weight.

*Nutrition-You are what you eat
**MyPyramid plan offers a personalized approach
MyPyramid divides food into 6 groups and gives you recommendations on what to eat from each group. This system includes plans appropriate to different calorie levels of food intake, based on the latest Dietary Guidelines for Americans issued by the USDA and the Dept. of Health and Human Services. If you enter your age, gender, and activity level on the MyPyramid web site, the system will match you with the best plan for your needs.
General recommendations for healthy diet include:
-Eat a variety of foods –Maintain a healthy weight –Eat plenty of fruits, veggies and whole-grain products –Choose a diet low in cholesterol and saturated fat -Use sugar only in moderation -Consume salt and sodium in moderation (less than 2,300mg per day) -Drink alcohol only in moderation (one drink a day for women, or 2 for men)

( 4/21/2012)

**Carbohydrates: A major energy source
Carbs= one of the body’s main sources of energy, and many nutritionists recommend that appx 45-65% of our calorie intake come from carbs. Carbs can either be simple or complex; simple carbs (sugars)-are found in natural foods such as fruit and honey, complex carbs-include glycogen and starch, they consist of many sugar units linked together.
**Lipids: Essential cell components and energy sources
Phospholipids and cholesterol make up most of the cell membrane; cholesterol also forms the backbone of steroid hormones and is used to synthesize bile. Fat stores energy, cushions organs, insulates the body under the skin, and stores several vitamins.
Saturated Fats- have 2 hydrogen atoms for every carbon atom in their fatty acid tails. They tend to be solid at room temp, they are found primarily in meat and dairy products. They tend to raise blood levels of LDL cholesterol or “bad cholesterol”.
Unsaturated Fats- they are missing one or more pairs of hydrogen atoms in their fatty acid tails. Every missing pair of hydrogen atoms leads to a double bond between adjacent carbons and kink in the tail, making it more difficult for adjacent molecules to form bonds with each other. These fats are liquids at room temp, they tend to lower blood LDL cholesterol.
The liver can synthesize cholesterol and most of the lipids the body needs but it cannot produce every last one of them. Essential fatty acids= the few fatty acids that our bodies can’t make and must be consumed as food.
**Complete proteins contain every amino acid
Essential amino acids= the amino acids the body can’t produce, that must be ingested in food.
Complete protein-contains all 20 of the amino acids in proportions that meet our nutritional needs.
**Vitamins are essential for normal function
Vitamins= group of at least 13 chemicals that are essential for normal functioning. The body can produce only a few vitamins; our skin synthesizes vitamin D when exposed to sunlight, and bacteria living in the colon manufacture vitamins K, B6, and biotin.

Vitamins fall into 2 groups: fat soluble- are absorbed more readily if there is fat in the diet; and water soluble- absorbed more readily than fat-soluble vitamins, but they are stored only briefly and rapidly excreted in urine.

**Minerals: Elements essential for body processes
Minerals- atoms of certain chemical elements that is also essential for body processes. They are the ions in blood plasma and cell cytoplasm. They contribute to the activity of nerves and muscles.
**Fiber benefits the colon
Fiber- is an indigestible material found in many veggies, fruit and grains; and even though we can’t digest it, we still need a certain amount in our diets. Fiber is beneficial because it makes feces bulky and helps them pass more efficiently through the colon.
Low fiber diets can lead to chronic constipation, hemorrhoids, diverticulosis, and has also been associated w/a higher risk of colon cancer. Doctors recommend eating between 20-35 grams of fiber a day.

*Weight control: Energy consumed versus energy spent

Energy is measured in units called calories. Technically, a calorie is the amount of energy needed to raise the temp of 1 gram of water y 1 degree Celsius.
BMR: Determining how many calories we need
If we want to maintain a stable body weight, the number of calories we consume must equal the number we use. Your daily caloric energy needs are determined by your basal metabolic rate (BMR).
BMR can be influenced by the following factors:
-Gender and body composition: it is higher in males, muscle tissues consumes more energy than fat tissue.
-Age: your BMR declines over time
-Health: some conditions (such as fever) increase BMR, others such as hypothyroidism lower it.
-Stress: norepinephrine and epinephrine raise BMR.
-Food intake: eating increases metabolic rate, whereas fasting and extreme dieting decrease it.
-Genetics: Rates of metabolism vary between individuals; genes play a strong role in your BMR although it hasn’t precisely been determined how so yet.

( 4/21/12)

**Energy balance and body weight
-Healthy weight control involves balancing energy intake against energy expenditure. Fat contains about 9 calories/gram, but carbs and proteins only contain 4. When we eat more calories than we use, the excess energy is stored in specialized cells as fat. Research suggests that overweight people have 2 or 3 times more fat cells than normal weight individuals.

*Disorders of the digestive system
**Disorder of the GI tract
-Lactose intolerance: Difficulty digesting milk- human infants are born w/the enzyme lactase in their small intestines for digesting lactose; however many adults gradually lose the enzyme and with it their ability to digest lactose; which results in lactose intolerance. Symptoms include: diahhrea, gas, bloating, and abdominal cramps after ingesting milk products.

( 4/21/12)
-Peptic ulcers: Painful erosions of the mucosal lining of the stomach or duodenum. Most of them are associated w/ infection by one of the few bacteria that can live in the acidic environment of the stomach called helicobacter pylori. The bacterial infection can lead to chronic inflammation, an increase in gastric acid secretion and damage to the mucosal lining.
-Colon Polyps: noncancerous growths- A polyp is a noncancerous growth that projects from a mucous membrane. They can develop in many areas of the body, including the colon. Polyps can be detected and removed in a colonoscopy.

**Disorders of accessory organs
-Hepatitis: Inflammation of the liver- this is generally caused by viruses or toxic substances. Hep A is transmitted by contaminated food or water and causes a brief illness from which most people recover completely. Hep B travels in the blood or body fluids, so it is usually passed via contaminated needles, blood transfusion, or sexual contact w/infected individuals. Hep C is also transmitted in infected blood, usually through contaminated needles or blood transfusions.
-Gallstones can obstruct bile flow- Excessive cholesterol in bile may precipitate out of solution with calcium and bile salts, forming hard crystals called gallstones. If the crystals grow large enough they can obstruct bile flow and cause intense pain.
**Malnutrition: Too many or too few nutrients
-Malnutrition refers to conditions in which human development and function are compromised by an unbalanced or insufficient diet. Malnutrition can be caused by either over nutrition or undernutrition. Overnutrition can lead to obesity. However malnourishment is far more common deficiencies of one or more nutrients can produce specific effects: for example years of vitamin A deficiency a lead to eye damage and night blindness. In children, undernutrition stunts growth and increases susceptibility to infection.
**Obesity: A worldwide epidemic?
World Health Organization calls obesity a global epidemic; in the US obesity has increased from 12.6% of the population in 1990 to 34% in 2006. Body weight is determined by both internal factors and environmental factors.

*Eating disorders: Anorexia nervosa and bulimia
-Anorexia nervosa= condition in which person excessively diets or stops eating altogether, even to the point of starvation or death. Symptoms include: refusal to maintain healthy body weight; people with anorexia often weight less than 85% of their ideal weight. They have an intense fear of gaining weight, even though they’re underweight. They have a distorted perception or reoccupation with body weight or shape.

( 4/21/12)
-Bulimia= binge and purge condition in which one eats and deliberately vomits or takes other steps to minimize the calories ingested. Symptoms include: recurrent episodes of binge eating, taking recurrent inappropriate steps to prevent weight gain (such as self-induced vomiting, misusing laxatives, and enemas), and preoccupation w/body shape and weight.

( 4/21/12)

Chapter 11: Nervous System- Integration and Control

4 characteristics of nervous system:
-Receives information from many different senses simultaneously
-Nervous system integrates information; integration is process of taking different pieces of info from many sources and assembling the pieces into a whole that makes sense.
-Nervous system is very fast- it can receive info, integrate it and produce response within tenths of a second.
-It can initiate specific responses including muscle contraction, glandular secretion, and even conscious thought and emotions.

*The Nervous System has 2 principal parts
-Nervous system includes the central nervous system (CNS) and peripheral nervous system (PNS). The CNS consists of the brain and the spinal cord; it receives, processes, stores, and transfers information. The PNS has 2 functional subdivisions: the sensory division of the PNS carries information to the brain and spinal cord, and the motor division of the PNS carries information from the CNS to other parts of the body.
The somatic division of the PNS controls skeletal muscles, and the autonomic division of the PNS controls smooth muscles, cardiac muscles, and glands. In turn autonomic division has 2 subdivisions called the sympathetic and parasympathetic divisions.

( 4/29/12)

*Neurons are Communication cells of the Nervous System
-Neurons= cells specialized for communication. They generate and conduct electrical impulses also called action potentials from one part of the body to another. There are 3 types of neurons in the nervous system.
-Sensory neurons= part of the PNS, they are specialized to respond to a certain type of stimulus, such as pressure or light. They transmit info about this stimulus to the CNS in the form of electrical impulses.
-Interneurons= part of the CNS, they transmit impulses between components of the CNS; they receive input from sensory neurons, integrate this info and influence the functioning of other neurons.
-Motor Neurons= part of the PNS, they transmit impulses away from the CNS; they carry nervous system’s output, still in the form of the electrical impulses.

**All neurons consist of a cell body, one or more dendrites, and an axon.
-Cell body= main body of the neuron, it includes the nucleus with its content of DNA, and mitochondria and other cell organelles.
-Dendrites= receive info from receptors or incoming impulses from other neurons.
-Axons= long, slender tube of cell membrane containing a small amount of cytoplasm. They are specialized to conduct electrical impulses.

( 4/29/12)

*Neurons initiate action potentials
**Sodium-potassium pump maintains resting potential
-Sodium potassium pump is essential to the control of cell volume by virtue of its ability to remove osmotic particles from the cell. It is also essential for the development and maintenance of electrical charge across the cell membrane. Each time the sodium-potassium pump goes through a cycle, the net effect is the removal of one osmotic particle and also one positive charge. Sodium-potassium pump removes both osmotic particles and positive charges from the cell at the same time. As a result of the activity of the sodium-potassium pumps and also the presence of negatively charged protein molecules trapped within the cell, the cytoplasm has a slight excess of negative charge compared to the interstitial fluid.
Concentration of sodium is much higher in the interstitial fluid than it is in the cytoplasm, whereas the inverse is true for potassium.

**Graded potentials alter the resting potential
-Resting potential of a neuron undergoes a change when an impulse arrives from another neuron. Every incoming impulse produces a small transient charge in the resting potential in a local area of the membrane. Depending on the type of signal and its strength, the change might be to depolarize (move voltage closer to zero) or hyperpolarize (make it even more negative) the membrane. These transient local changes in resting potential are called graded potentials.

**Action Potential is a sudden reversal of membrane voltage
-If the sum of all graded potentials is sufficiently strong to reach a certain triggering membrane voltage called the threshold, an action potential results.
-Action potential= sudden temporary reversal of the voltage difference across the cell membrane. Once it is initiated, it sweeps rapidly down the axon at constant amplitude and rate of speed until it reaches the axon terminals. An action potential (impulse_ is the only form in which information is transmitted a long distance by the nervous system. These occur because the axon membrane contains voltage-sensitive ion channels that open and close sequentially once threshold has been reached. It has a sequence of 3 events:
1) Depolarization- sodium moves into the axon: when threshold is exceed voltage-sensitive sodium channels in the axon’s membrane open briefly and sodium ions diffuse rapidly into the cytoplasm. The influx of positive ions causes depolarization.
2) Repolarization: potassium moves out of axon- after a short delay the sodium channels close automatically. The reversal of the membrane polarity triggers the opening of potassium channels, which allows more potassium ions to diffuse rapidly out of the cell. The loss of positive ions from the cell leads to repolarization.
3) Reestablishment of the resting potential- Because the potassium channels are slow to close there is a brief overshoot of membrane voltage during which the interior of the axon is slightly hyperpolarized. Shortly after the potassium channels close the resting potential is reestablished.

**Action potentials are all-or-none and self-propagating
-An action potential does not occur unless a certain threshold membrane voltage is reached. Once it is triggered, it always looks exactly the same in form and voltage. A certain amount of pressure-the threshold level- is required to make the action potential start. Too little amount of pressure will cause it to not start, while too much pressure makes it start more quickly. An action potential also continues to propagate itself in the next region of the axon; because of the local spread of electrical current forward from the region of the axon that is currently undergoing an action potential brings the next region of the axon to threshold. Therefore the action potential is propagated continuously down the axon like a moving wave, at a constant rate of speed and amplitude.

*Neuroglial cells support and protect neurons
-Neuroglial cells= provide physical support and protection to neurons and help maintain healthy concentrations of important chemicals in the fluid surrounding them. In the PNS many neuron axons are protected by Schwann cells (which produce fatty insulating material called myelin). During development Schwann cells wrap themselves around a short segment of an axon many times as a sort of insulating blanked, creating a shiny white protective layer around the axon called a myelin sheath. Between adjacent Schwann cells are short uninsulated gaps called nodes of Ranvier, where the surface of the axon is still exposed.
**Myelin sheath around the axon serves 3 important functions:
1) Saves the neuron energy- the insulating layer of myelin prevents some of the slow inward leak of sodium and outward leak of potassium.
2) It speeds up the transmission of impulses- the myelin sheath prevents nearly all leakage of charged ions across the axon membrane except where the axon is bare. When an action potential occurs at a node of Ranvier, then the local depolarizing current spreads much farther within the axon, all the way to the next node of Ranvier. The rate of travel of this local current within the axon is even faster than the rate of travel of a continuously propagated action potential along the unmyelinated axon.
3) Helps damaged or severed axons of the peripheral nervous system regenerate- if a neuron axon is severed, the portion of the axon distal to the cell body may degenerate. Depending on the length of the axon, the regeneration process can take anywhere from a few weeks to more than a year.

*Information is transferred from a neuron to its target
Once an action potential reaches the axon terminals of a neuron the info inherent in it must be converted to another form for transmittal to its target. Neurotransmitter= chemical that is released and crosses the synapse between 2 cells; it transmits a signal from a neuron to its target.
**Neurotransmitter is released
-Presynaptic membrane= cell membrane of the neuron that is sending info, postsynaptic membrane is the membrane of the cell that is about to receive the info, the synaptic cleft= small fluid-filled gap that separates the presynaptic and postsynaptic membranes. Each axon terminal of the presynaptic neuron ends in an axon bulb that contains neurotransmitter stored in membrane-bound vesicles.
**The events that occur during a synaptic transmission follow a pattern
1) Action potential arrives at axon bulb, causing calcium channels in the presynaptic membrane to open.
2) Presence of calcium causes the vesicles to fuse with the presynaptic membrane and release their contents of neurotransmitter directly into the synaptic cleft.
3) Molecules of neurotransmitter bind to receptors on the postsynaptic membrane. This causes certain chemically gated channels to open.
4) Sodium ions diffuse inward, producing a graded depolarization of the postsynaptic membrane in the area of the synapse.

**Neurotransmitters exert excitatory or inhibitory effects
-Scientists have ID’d more than 50 chemicals that can function as neurotransmitters. All are stored in vesicles within the axon bulb and released into the synaptic cleft in response to an action potential. All produce graded potential in the postsynaptic cell. Neurotransmitters are classified as excitatory, inhibitory, or both.
Excitatory= encourage the generation of new impulses in the postsynaptic neuron.
Inhibitory= cause the postsynaptic cell to hyperpolarize, meaning the cell’s interior becomes even more negative than before.
Depending on the type of receptor to which the neurotransmitter binds to then they can be both excitatory and inhibitory.

**Postsynaptic neurons integrate and process information
-The conversion of the signal from electrical to chemical allows the postsynaptic cell to do a lot of integration and info processing. This is because a single all-or-none action potential in the presynaptic neuron does not always cause a corresponding all-or-none action potential in the postsynaptic neuron, as it does in a muscle cell.
One way for the threshold to be reached in a postsynaptic neuron is for the presynaptic neuron to increase their frequency of stimulation, sending lots of action potentials in a short time. In addition to stimulus intensity, other factors affecting whether threshold is reached in the postsynaptic neuron include: 1) how many other neurons form synapses with it, and 2) whether those synaptic connections are stimulatory or inhibitory.

Chapter 12: Sensory Mechanisms

*Receptors receive and convert stimuli
-Stimulus= some change within or outside the body; it is often a form of physical energy such as heat, pressure, or sound waves, but it can also be chemical
Receptor= a structure specialized to receive certain stimuli; it accepts the stimulus and converts its energy into another form.
-Some receptors are evolved from dendritic structures of a sensory neuron; these convert the stimulus into an impulse within the sensory neuron, and if the impulse is powerful enough it initiates an impulse within the sensory neuron.
-When the CNS receives these impulses we often experience a sensation, meaning that we become consciously aware of the stimulus.
**Receptors are classified according to the stimulus
-Mechanoreceptors: respond to forms of mechanical energy, such as waves of sound, changes in fluid pressure, physical touch, or forces generated by gravity/acceleration
-Thermoreceptors: receptors that respond to heat or cold.
-Pain receptors: receptors that respond to tissue damage or excessive pressure/temperature.
-Chemoreceptors: receptors that respond to the presence of chemicals in the nearby area.
-Photoreceptors: receptors that respond to light.
**The CNS interprets nerve impulses based on origin and frequency
-Stronger stimuli activate more receptors and trigger a greater frequency of impulses in sensory neurons. In effect, the CNS gets all the info it needs by monitoring where impulses originate and how frequently they arrive.
**Some receptors adapt to continuing stimuli
-Receptor adaptation= the sensory neuron stops sending impulses even though the original stimulus is still present; this explains why the CNS can ignore one sensation in order to concentrate on another.
Receptors in the skin for light touch and pressure adapt rather quickly; which provides and advantage because they can keep the CNS informed of changes in these stimuli, without constantly bombarding it with relatively unimportant stimuli. Olfactory receptors also adapt quickly, which can be harmful because people can be continually exposed to low levels of hazardous chemicals that they can no longer smell.
-Pain receptors, joint receptors, and muscle receptors adapt slowly or not at all. Their lack of adaptation is advantageous because persistent sensations such as pain alert us to possible tissue damage from illness or injury and prompt us to take appropriate action.
**Somatic sensations and special senses provide sensory information
-Somatic sensations originate from receptors present at more than one location in the body. These sensations include temperature, touch, vibration, pressure, pain, and awareness of body movements and position. The 5 “special senses” (taste, smell, hearing, balance, and vision) originate from receptors that are restricted to particular areas of the body, such as ears and eyes.

*Somatic sensations arise from receptors throughout the body
-Somatic sensations are essential to help us coordinate muscle movements, avoid danger, and maintain body temp. Some somatic sensations contribute to pleasurable feelings as well, such as our response to the gentle touch of a loved one. Receptors that detect somatic sensations are located throughout the body in skin, joints, skeletal muscles, tendons, and internal organs.

*Mechanoreceptors detect touch, pressure, and vibration
-All mechanoreceptors are modified dendritic endings of sensory neurons. Any force that deforms the plasma membrane of the dendritic ending produces a typical graded potential. If the graded potential is large enough to exceed the threshold, the sensory neuron initiates and impulse.
-Unencapsulated dendritic endings= naked dendritic endings of sensory neurons around hairs and near the skin surface signal pain, light pressure and changes in temperature.
-Merkel disks: these are modified unencapsulated dendritic endings that detect light touch and pressure.
-Meissner’s corpuscles: These are encapsulated touch receptors located close to the skin surface that detect the beginning and the end of light pressure and touch.
-Ruffini endings: These are encapsulated receptors that respond continually to ongoing pressure.
-Pacinian corpuscles: These are encapsulated receptors that are located in the dermis that respond to either deep pressure or high-frequency vibration.
**Mechanoreceptors indicated limb position, muscle length and tension
-Muscle spindles: mechanoreceptors that are specialized for monitoring muscle length; for most joints muscle length determines joint position because of the way the muscle is attached to the bones. Muscle spindles are small bundles of modified skeletal muscle cells located within a skeletal muscle. They are innervated by sensory nerves whose dendritic endings are mechanoreceptors that respond to stretch.

( 4/29/12)

( 4/29/12)

**Thermoreceptors detect temperature
-Near the skin’s surface thermoreceptors for heat and cold provide useful info about the external environment. These receptors adapt quickly, allowing us to monitor changes in temp accurately and yet adjust sensory input so it becomes more bearable. Other receptors located in the abdominal and thoracic organs throughout the body monitor internal temperature.
**Pain receptors signal discomfort
-Pain warns us to avoid certain stimuli and informs us of injuries. Pain receptors are unencapsulated endings that respond to injury from excessive physical pressure, heat, light, or chemicals.
Fast pain: also called sharp or acute pain, occurs as soon as a tenth of a second after the stimulus. Receptors for fast pain generally respond to physical pressure or heat and usually are located near the surface of the body. They inform us of stimuli to be avoided.
-Slow pain: this pain generally arises from muscles or internal organs; it may not appear until seconds or even minutes after energy, and it’s due to the activation of chemically sensitive pain receptors by chemicals released from damaged tissue. Referred pain= slow pain from internal organs that is often perceived as originating from an area of the body completely removed from the actual source.

*Vision: Detecting and Interpreting visual stimuli
**Structure of the eye
-Sclera: the tough outer coat also known as the “white of the eye”, this covers and protects it
-Cornea: transparent anterior portion of the eye, it bends the incoming light (or focuses it)
-Iris: a colored, disk-shaped muscle that determines how much light enters the eye
-Pupil: the adjustable opening in the center of the iris, light passes through this to the lens
-Aqueous humor: fluid that nourishes and cushions the cornea and lens.
-Lens: a transparent, flexible structure attached by connective tissue fibers to a ring of circularly arrange ciliary muscle
-Vitreous humor: transmits light to the retina.
-Retina: made up primarily of photoreceptor cells, neurons and a few blood vessels, it absorbs light and converts it into impulses.
-rods= photoreceptors responsible for black and white vision in dim light
-cones: photoreceptors responsible for color vision and high visual activity
-Macula: central region of the retina with the highest density of photoreceptors
-Optic nerve: located at the back of the eye, it carries info to the thalamus to be forwarded to the visual cortex for interpretation.
-Optic disk: area where the axons of the optic nerve and associated blood vessels exit the eye also referred to as the “blind spot” of the eye.

( 4/29/12)

( 4/29/12)

**Regulating the amount of light and focusing the image
-The iris adjusts the amount of light entering the eye with 2 sets of smooth muscle. When bright light strikes the eye, contraction of muscles arranged circularly around the pupil causes it to contract; otherwise the intensity of daylight would overwhelm our photoreceptors and temporarily blind us.
Light entering the eye is focused by the cornea and the lens. The cornea is responsible for bending most of the incoming light. Our ability to regulate the degree to which incoming light is bend and therefore our ability to change focus between near and far objects is accomplished solely by adjusting the curvature of the lens, this is done by the ciliary muscle.
-When ciliary muscle contracts the inner radius of the muscle shrinks reducing the tension on the fibers attached to the lens. This allows the lens to bulge, and we focus on a near object. When the ciliary muscle relaxes, the ring of muscle increases the tension on the lens, stretching and flattening it and bringing more distant objects into focus.
**Eyeball shape affects the focus
-Myopia: common inherited condition in which the eyeball is slightly longer than normal. Even when the lens is flattened maximally, distant objects focus in front of the retina; this causes nearsightedness.
-Hyperopia: occurs when the eyeball is too short and nearby objects focus behind the retina; this causes farsightedness.

**Light is converted into action potentials
-The unique structure of the retina allows us to see in color, adapt to varying light intensities and perceive images of the world around us.
-Outermost layer of retina consists of pigmented cells that absorb light not captured by the photoreceptor cells.
-Next is a layer of photoreceptor cells called rods and cones.
-Rods and cones synapse w/the 3rd layer; a layer of neurons called bipolar cells, which partially process and integrate info and then pass it on to the 4th layer.
-Innermost layer consists of ganglion cells; which are also neurons, and their long axons become the optic nerve going to the brain.
**Rods and cones respond to light
-One end of photoreceptor cells consists of a series of flattened disks arranged to form either a rod or cone shaped structure. These flattened disks contain numerous molecules of a particular light-sensitive protein called a photopigment. A photopigment protein u undergoes a change of shape when it is exposed to energy in the form of light. The change in the photopigment molecule shape causes the photoreceptor to close some of its sodium channels and reduce the amount of neurotransmitter it normally releases.
-There are around 120 million rods and 6 million cones, but only 1 million ganglion cells w/axons going to the brain.
**Rods provide vision in dim light
-Rods all have the photopigment called rhodopsin; it is much more sensitive to light than the photopigments in cones, and therefor in dim light our vision is dependent primarily on rods; rods however do not give us color vision, which is why objects appear less colorful in dim light.

**Cones provide color vision and accurate images
-WE have 3 different kinds of cones: red, green, and blue; each of these contains a photopigment that absorbs energy of red, green, or blue light. We can distinguish a variety of colors because of the way the brain interprets the ratios of impulses coming from the ganglion cells connected to the 3 types of cones. When all 3 types are activated by all different wavelengths we perceive white light; the perception of black is no white at all. Cones require stronger light to be activated because the cone photopigments are much less sensitive to light than the rhodopsin in rods; this is why your ability to distinguish between colors declines in dim light and it becomes difficult to tell whether a dark-colored car is green or red. When light is dim we primarily see w/rods, so we mainly see in black and white.

**Visual Receptors Adapt
-Adaptation depends on rapid adjustment of the pupil by the iris and on adaptation of the rods. The absorption of light by rhodopsin used up the photopigment temporarily; Light energy actually breaks the rhodopsin into 2 molecules, they can resynthesize back into rhodopsin, but only aver a few minutes.

*Disorders of sensory mechanisms
**Disorders of the ears
-Deafness: loss of hearing- it can have many different causes; deafness caused by damage to hair cells is called nerve deafness, because sounds can’t be converted into impulses is sensory nerves; this is usually the result of frequent exposure to loud sounds. Damage to the tympanic membrane or bone of the middle ear is called conduction deafness; in this type the sound waves aren’t transferred to the inner era at all, it can be caused due to arthritis of the middle ear bones.
-Otitis media: inflammation of the middle ear- This usually results from an upper respiratory infection that extends up the auditory tube; the tube may become blocked and trap fluid in the middle ear.
-Meniere’s syndrome: inner ear condition impairs hearing and balance- the cause of this is unknown, but it could be due to excess fluid in the cochlea and semicircular canals. Symptoms include repeated episodes of dizziness and nausea accompanied by progressive hearing loss. Balance is usually affected to the point that people find it hard to even stand upright.

**Disorders of the eyes
-Retinal Detachment: retina separates from choroid- If the retina is torn the vitreous humor may leak through the tear and peel the retina away from the choroid. Most common cause is a blow to the head. The detached region of the retina loses most of its blood supply and its ability to focus an image properly.
-Cataracts: The lens becomes opaque- Cataracts are a decrease in the normal transparency of a lens. If the delivery of nutrients to the lens is not sufficient, these proteins may denature, or clump, making the lens opaque. Most cataracts are age-related or secondary to diabetes or other diseases.
-Glaucoma: Pressure inside the eye rises- This is the condition in which the drainage vessel that drains the aqueous humor becomes blocked; the excess fluid increase pressure inside the eye and compresses blood vessels supplying the retina. Cells of the retina/optic nerve may eventually die, ultimately leading to blindness.
-Age related macular degeneration (AMD) – This is a disease of visual impairment caused by detachment of the retina and degeneration of photoreceptor cells in the macular region of the retina. The most common cause is accumulations of cellular debris between the choroid and the retina.
-Color Blindness: Inability to distinguish the full range of colors- This is when people have the inability to distinguish the full range of colors. Most color blindness is caused by the deficient numbers of particular types of cones. The most common type is red-green color blindness, which is when you’re deficient in red and green cones; people have a hard time distinguishing between the 2 colors and perceive them as the same color. Red-green color blindness is an X-linked recessive trait that is more common in men than women.

Chapter 24: Human impacts, Biodiversity, and Environmental Issues
The human capacity to shape the environment both creatively and destructively is causing global changes in biogeochemical cycles and affecting the populations of nearly all living species.

*Pollutants impair air quality

-The air we breathe is a mixture of primarily nitrogen, and oxygen, w/trace amounts of carbon dioxide. It also contains trace amounts of chemicals or particles that have adverse effects on living organisms, which are known as pollutants. The major concerns regarding air pollution fall into 4 areas: Global warming, destruction of the ozone layer, acid precipitation, and smog production.
**Excessive greenhouse gases lead to global warming
-Greenhouses gases are located in the stratosphere, these gases that allow sunlight to penetrate through them, but as the sunlight is converted to heat, it doesn’t allow them to escape. The most significant greenhouse gas is water vapor, which accounts for appx 60% of the total. The remainder are human made, and consist of CO2, CH4, and N20, with small amounts of CFCs. Together the greenhouse gases produce a greenhouse effect; which allows sunlight to come to Earth but traps most of the heat radiated from Earth on its way to space. Without the greenhouse effect, most of the sun’s heat would radiate away from Earth and the avg temperature would be well below freezing.
The general agreement among scientists today is that the excessive production of greenhouse gases (throughout earth’s history) is increasing the greenhouse effect and raising the average global temperature- this is referred to as global warming.
-The main activities that cause raises in atmospheric CO2 are the burning of fossil fuels for energy (the carbon in fossil fuels comes from decayed plant material, and we release the carbon back into the air as CO2), and deforestation (because the trees would absorb CO2 from the air during photosynthesis).

( 5/6/12)

**CFCs deplete the ozone layer
-Ozone (O3) is found in 2 places in the atmosphere; in the troposphere (layer near the planet surface) ozone is an air pollutant formed by the reaction of oxygen w/automobile exhaust and industrial pollution. Ozone is mildly toxic; it causes plant damage and respiratory distress. Higher up in the atmosphere ozone is actually very beneficial; it forms a thin layer of the stratosphere that helps shield the Earth from UV rays.
In the early 1980s it had become apparent that the stratospheric ozone layer was suffering damage due to CFCs (group of chemicals used in refrigerators, air conditioners, and aerosol sprays). CFCs released near ground level migrate slowly upward toward the stratosphere and decompose, releasing chlorine atoms; these chlorine atoms combine w/ozone and destroy it, producing oxygen. The chlorine molecule can be used over and over in the reaction, so it can destroy as many as 10,000 ozone molecules.

**Pollutants produce acid precipitation
-Major source of acid precipitation is sulfur dioxide, which is released into the air as a result of burning high-sulfur coal and oil for power, a secondary source is nitrogen oxide in automobile exhaust. Sulfur dioxide and nitrogen oxides combine w/water vapor in the air, become sulfuric acid and nitric acid, and dissolve in raindrops, which falls as acid precipitation. This precipitation corrodes metal and stone and damages forests and aquatic ecosystems, particularly in the northeastern United States, southeastern Canada, and Europe.
**Smog blankets industrial areas
-Several pollutants in air react w/each other in the presence of sunlight and water vapor; they form a hazy brown or gray layer of smog that tends to hover over the region where it is produced. Most smog is caused by the burning of fossil fuels by automobile exhausts. Smog contains several chemicals that irritate the eyes and lungs and may lead to chronic respiratory illness.
Smog can become especially troublesome during a thermal inversion; which is when a warm stagnant upper layer of air traps a cooler air mass containing smog, beneath it.

*Pollution jeopardizes scarce water supplies
**Water is scare and unequally distributed
-All of the freshwater on the surface of the land and in aquifers forms less than 1% of Earth’s total water. Over 97% is salty ocean water, and 2% is frozen in glaciers and polar ice caps. Water isn’t evenly distributed among human populations, residents of the more industrialized use 10 to 100 times more water than people in less industrialized countries. When we use water for our own purposes we take it away from other species or limit their normal migration patterns.
**Urbanization increases storm water runoff
-In urban areas, the shift from woodlands and fields to impermeable roads and buildings has caused major stormwater runoff problems. On the U.S. East Coast, stormwater combines w/sewage leading to combined sewage overflow (CSO). 28 billion gallons of CSO impact the New York Harbor each year; this is the major source of pathogens in the area, it causes gastroenteritis, eye and ear infections, skin rashes, respiratory infections, and hepatitis in swimmers and kayakers.
**Human activities pollute freshwater
-Untreated sewage, chemicals from factories, the runoff of pesticides and fertilizers, and rubber and oil from city streets, all must go somewhere. Either they degrade chemically according to their natural cycle of decomposition r they end up in water or soil.
Some water pollutants are organic nutrients that arise from sewage treatment plants, food-packing plants, and paper mills. When those nutrients are degraded by bacteria, the rapid growth rate of bacteria can deplete the water of oxygen, threatening aquatic animals.
-Other water pollutants are inorganic nutrients, such as nitrate and phosphate fertilizers and sulfates in laundry detergents; these cause prolific growth of algae, which die and are also decomposed by bacteria.
Eutrophication refers to rapid growth of plant life and the death of animal life in a shallow body of water as a result of excessive organic or inorganic nutrients; this is part of the process that turns freshwater into marsh, and then dry land.
-Toxic pollutants can become more concentrated in the tissues of organisms higher up the food chain, which is known as biological magnification. Biological magnification occurs because each animal in a food chain consumes many times its own weight in food throughout its lifetime. Best example of biological magnifications the heavy metal mercury. Mercury released into the air or on the land often ends up in aquatic ecosystems, where it accumulates by biological magnification in tertiary consumes such as sharks, tuna, and whales.
**Oil pollution damages ocean shorelines
-In most years several million tons of oil enters the world’s oceans. About 50% comes from natural seepage; therefore some oil pollution is a natural phenomenon. However, 30% of the total oceanic oil pollution is caused by oil disposal on the land that is washed into the sea in streams and rivers. In general when oil is spilled at sea about a quarter evaporates, nearly half eventually is degraded by bacteria, and the remaining quarter eventually settles to the ocean floor. In short term, however an oil spill can cause significant damage to marine and shoreline ecosystems.

*Pollution and overuse damage the land
-The main environmental issue isn’t actually how we pollute the land, but how much of the land we use. WE dam river valleys to produce hydroelectric power, strip mountaintops to find coal, and cut down forests for lumber or to clear space for crops.
-AS the human population grows, people tend to migrate toward cities. Cities often expand into nearby farmland because it is more economical to build where it is relatively flat.
Many people rely almost entirely on their local environment to survive; therefor it’s not uncommon for impoverished rural communities to cut down all trees for fuel and shelter. Stripping the biomass from fragile ecosystems leads to erosion and desertification (transformation of marginal lands into near-desert conditions unsuitable for future agriculture); every year an estimated 15 million more acres become desert.

( 5/6/12)

Global Warming in the News Today
As of today the US, Mexico, Bangladesh, Sweden, the UN, Canada, and Ghana joined together in efforts to start that will help to address the global warming problems caused by more short-lived pollutants from our environment, including soot, methane, and hydrofluocarbon; which as of today account for between 30-40% of global warming.
According to research, the efforts put forth by these countries can lower the earth’s temperature by 0.5 degrees Celsius by 2050, and also reduce the amount of cases of lung and heart disease by the year 2030. (5/6/12)

April 16, 2012

Chicken Leg Dissection

Filed under: Uncategorized — brewoods90 @ 3:52 am

Chicken Leg Dissection
In this lab I will dissect a chicken leg, and identify what types of tissues I find, and the functions of these tissues.

I started off the lab by washing and drying the chicken thigh.

The chicken thigh

I then began to remove all of the skin and fatty tissue by cutting through the connective tissue that connected it to the underlying muscles (there were more than one layer; I could tell because they had distinct outlines The muscles were a pinkish color and were striated.
As I was cutting through the connective tissue I noticed little white clumps of fat (adipose) tissue; when I picked it off of the chicken it felt squishy and rubbery. The job of the fat is to store extra energy, and can also be used for insulation, in order to help keep out body temperature up.

The connective tissue attaching skin to underlying tissues

Single Chicken muscle

The tendons were white, stretchy, yet surprisingly strong, and string-like.

Then tendon, which connects muscles to bones

The joint moves in a hinge-like fashion (a hinged synovial joint). The joint is covered by hyaline cartilage; if this cartilage were to wear away in a joint then the chicken would have gotten osteoarthritis, and the bone could have thickened over time, which would restrict the joint movement even more. In order to reduce the friction and delay the wearing down of cartilage, this joint has disks of cartilage called menisci, and 13 fluid filled sacs called bursa.

If were had been able to cut into the chicken bone I imagine we would have seen a sponge-like bone. Inside the bone there would have been red bone marrow, which houses the stem cells responsible for making red blood cells, white blood cells, and platelets.
Types of white blood cells: neutrophils, eosinophil’s, basophils, monocytes, and lymphocytes.

This lab helped me to get a more hands on feel for how the muscles, bones, tendons, and ligaments all work together in our body. I also learned what all of these different tissues looked and felt like.

April 15, 2012

Unit 3 Compilation

Filed under: Uncategorized — brewoods90 @ 5:31 pm

Unit 3 compilation-part 2

March 12, 2012

Lab 2-Part 2- RNA & DNA

Filed under: Uncategorized — brewoods90 @ 1:13 am

Lab Project 2: Part 2

Introduction: Transcribe a chain of DNA into RNA, and then translate it into a polypeptide. Then build a model of DNA using the translation that I created.
For my model, I will be using pipe cleaners, beads, and straws. The beads and pipe cleaners are used for the 2 sides of the helix. The straws are used for the base pairs of proteins. I will then attach the top of the model to a hanger and twist the bottom of it to make it look more like a realistic strand of DNA.

DNA PROTEINS= Guanine Cytosine Adenine Thymine
RNA PROTEINS= Guanine Cytosine Adenine Uracil

When a DNA strand and RNA strand pair up then: Guanine from DNA pairs with Cytosine from RNA
Cytosine from DNA pairs with Guanine from RNA
Adenine from DNA pairs with Uracil from RNA
Thymine from DNA pairs with Adenine from RNA

When 2 DNA strands pair up

Guanine and Cytosine pair up
Thymine and Adenine pair up



This was a fun lab for me to do, give us a chance to be crafty and learn at the same time! It surprised me that there was only one stop code in the polypeptide chain from my RNA strand, I had assumed those would be more common, but I learned that they’re not quite as common as I had thought! It is amazing to me how large the entire human genome is, and to think about how even the slightest mutation in one of the proteins/genes can have such a large impact on our lives.

March 11, 2012

Unit 2 Lab-Part 1: My chromosome

Filed under: Uncategorized — brewoods90 @ 2:54 pm

Lab Project 2: Part 1-My Chromosome
Chromosome 23- Y chromosome
Intoduction: In this lab I was assigned chromosome number 23, which is a sex chromosome, and I chose to do the Y chromosome. The assignment is to take 8 of the different genes found on the chromosome and give a description of what each gene is, what it is used for, etc. Then after I describe the 8 genes, I will pick the one that was most interesting to me and explain why I feel it is the most interesting out of the bunch.

SHOX- Short Stature Homebox- protein coding gene: Belongs to paired homebox family (involved in regulation patterns of anatomical development []). Defects in these genes are associated with inability to create enough human grown hormones.

CRLF2- cytokine receptor-like 2 factor: Protein coding gene. Receptor for the thymic stromal lymphopoietin (TSLP). TSLP plays important role in the maturation of T-Cells through the activation of antigen presenting cells (

SLC25A6-solute carrier family 25 (mitochondrial carrier; adenine nucleotide translocator), member 6: Protein coding gene. Product of this gene functions as a gateway that relocates ADP from the mitochondria into the cytoplasm.

ASMT-acetyl serotonin O-methyltransferase: Protein coding gene. Belongs to the methyl transferase superfamily (enzymes that transfer a methyl group from a donor to a receptor []. Located at the end of the X & Y chromosomes. The encoded enzyme catalyzes final reaction synthesis of melatonin. It is abundant in the Pineal gland.

SRY- sex determing Y Region: Protein coding gene. Member of high mobility group (HMG) box family of DNA binding proteins (group of proteins that help with transcription, replication, recombination, and DNA repair []). Mutations in this gene give rise to Swyer Syndrome (person is externally female with underdeveloped gonads []).

ZFY- zinc finger protein Y-linked: Protein coding gene. Encodes zing-ginger containing protein that could function as a transcription factor in DNA. Was once believed to be the testis determining factor and was referred to as TDF.

TSPY1-testis specific protein Y-linked 1: Protein coding gene. Protein encoded by this gene is only found in testicular tissue and may be involved in spermatogenesis (production of sperm). There are only approximately 35 copies of this gene present in humans.

DDX3Y-DEAD (Asp-Glu-Ala-Asp) box polypeptide 3, Y-linked: Protein coding gene. Implicated in a number of cellular processes, involving alteration of RNA secondary structures (such as translation initiation), nuclear and mitochondrial splicing, and ribosome and splicesome assembly. Some are believed to be involved in embryogenesis (development of embryo), spermatogenesis and cellular grown/division. Mutation in this gene causes male infertility.

To me the TSPY gene was the most interesting. It is interesting to me because it is believed to be involved in the process of spermatogenesis. If Annabelle’s [my 2 year old daughter] biological father would have either had a mutation in this gene, or completely had a lack of this gene then my daughter would be non-existent today. So, I am definitely thankful that this gene is present!

I learned quite a bit of information from this part of the lab! I had never even thought to do any type of research on one type of genes were found on which chromosomes before. I found that a lot of the genes have to deal with reproduction, because the Y chromosome is a sex chromosome. It was interesting to read what types of diseases even the slightest mutations on this chromosome could cause.

March 10, 2012

Unit 2 Compilation

Filed under: Uncategorized — brewoods90 @ 4:06 pm

Unit 2 Compilation
Table of Contents
Chapter 17: Cell Reproduction and Differentiation
Cell Cycle, Replication/transcription/translation, Cell Reproduction, Cell reproduction regulation, Environments influence on cell differentiation, Cloning organisms using undifferentiated cells, Therapeutic cloning,
Chapter 18: Uncontrolled Cell Division and Differentiation
Tumors (benign or cancerous), Cancer cells loss of control/function, Development of cancer, Early Detection, Cancer Treatments, Top 10 Cancers, Prevention of Cancers
Chapter 19: Genetics and Inheritance
Your genotype, Genetic inheritance, other dominance patterns, other factors influence inheritance patterns and phenotype, Sex-Linked inheritance: X & Y chromosomes carry different genes, Chromosomes may be altered in number or structure, Many Inherited genetic disorders involve recessive alleles,
Chapter 20: DNA Technology and Genetic Engineering
DNA Sequencing reveals structure of DNA, DNA Can be cloned in the Laboratory, Genetic Engineering Creates Transgenic organisms, Gene Therapy

Chapter 17- Cell Reproduction and Differentiation
The Cell Cycle-
Interphase: part of cell cycle in which the cell grows and its’ DNA gets duplicated
G1 phase= period of interphase that begins at the end of the last cell division and ends at the beginning of DNA synthesis (“first gap”)
S Phase= DNA is synthesized and the cell’s chromosomes are duplicated
G2 phase= cell prepares itself for division (“second gap”)
Mitotic Phase: Period during which the cytoplasm and nucleus divide
Mitosis: DNA is divided into 2 sets and the nucleus divides
Cytokinesis: “daughter” cells are formed from division of cytoplasm
(Entire cell cycle only takes about 18-24 hours)

Replication, transcription and translation
DNA= double stranded string of nucleotides intertwined into a helical shape. Chromosomes= organize and arrange DNA within the nucleus; humans have 46 chromosomes (23 pairs) in their nuclei.
Chromosomes aren’t visible throughout most of the cell cycle (they are collectively seen as chromatin during interphase) due to the fact that they’re so long and thin. Just before the nucleus divides they condense, which helps to keep the chromatin from breaking at this point. The duplicated chromosome consists of two “sister chromatids” connected by a centromere.
Gene= short segment of DNA which contains the code for one/more proteins (one gene is the smallest functional unit of DNA), there are about 20,000 genes on the 46 chromosomes in DNA
RNA =nucleic acid which carries out DNA’s instructions for protein synthesis
Messenger RNA (m RNA) = complements DNA, and carries out the genetic message to the cytoplasm
DNA replication: must take place before the cell can divide- begins with the uncoiling of the DNA helices- (recall that thymine/ adenine are paired and guanine/cytosine are paired, the fact that they’re paired ensures that after the DNA “unzips” then the complementary strand that is formed is exactly like the original) – the DNA strands don’t completely detach from one another, just detach at certain points creating “replication bubbles”, and at these points the complementary strands begin to form. They form outward in different directions until the replication bubbles join.
Mutations: alterations in DNA; can result from mistakes made during DNA replication, or chemical/physical forces can damage it. If these mutations aren’t corrected before DNA replication it could pass these mutations onto the future cells, or can hinder the replication process. Mutations in somatic cells (which could cause cancer, etc.) aren’t passed onto offspring; mutations in gametes can be passed onto offspring.
Transcription: process in which DNA code of a single gene is converted into a complementary single strand of m RNA. Main differences between DNA replication and transcription are: only the segment of DNA representing one gene unwinds; only one strand of DNA carries the genetic code specifying synthesis of RNA since RNA is only a single strand; Uracil replaces Thymine for the bases; Ribose is the sugar of RNA.
Promoter: unique base that marks the beginning of the gene. Polymerase: enzyme that attaches to promoter that starts the DNA unwinding process. The process ends at the other base sequence which ID’s the end of the gene. Introns: sections of the primary transcript of RNA that are snipped out because they don’t contain useful info. Exons: the sequences of the primary transcript that contain useful genetic info.
M RNA: the RNA molecule that is produced after the introns are snipped out of the primary transcript. Codon: 3 base sequence on the m RNA that codes a specific amino acid.
Translation: process of using m RNA to translate the code into a precise sequence of amino acids that makes up a certain protein.
Transfer RNA: carry the code for one amino acid; also carry an anticodon, which is a base triplet that is complementary to a codon of m RNA. Transfer RNA has the job of capturing a single amino acid and bringing it to the appropriate spot on the m RNA chain.
Ribosome RNA: RNA component of the ribosome, it has the binding sites for m RNA and t RNA; also contains enzymes that bind amino acids together.
3 steps of translation:
Initiation: the t RNA that carries the “start” codon binds to smaller ribosome subunit and the “start” codon of m RNA (AUG); the larger ribosome subunit joins these two together.
Elongation: chain of amino acids lengthens (one at a time). The t RNA captures free amino acids and brings them to the appropriate codon on the m RNA. The ribosome binds to the t RNA as the m RNA passes between the subunits. Once the bond is catalyzed the t RNA is then released.
Termination: Once a “stop” codon is encountered on m RNA then the ribosomal subunits detach from the m RNA.

Cell Reproduction
Mitosis: division of the nucleus- ensures that all cells of a complex organism have the same set of DNA. Mitosis produces diploid cells, which are cells with 46 chromosomes (in diploid cells there are 22 pair of autosomes, chromosomes aren’t sex chromosomes, plus the X&Y sex chromosomes).
Prophase: spindle forms (spindle= parallel arrangement of microtubules made up of cytoskeleton), centrioles move to opposite sides, the chromosomes become visible.
Metaphase: duplicated chromosomes align at center of cell
Anaphase: duplicate DNA molecules separate and move towards opposite sides of cell.
Telophase: begins when the 2 sets of chromosomes arrive at opposite sides of cell. Nuclear membrane forms around each group of chromosomes, chromosomes unwind and then cytokinesis begins.
Cytokinesis: cell divides to produce the 2 daughter cells. Contractile ring of protein filaments form inside the cell membrane; these filaments tighten and pinch the cell in 2.
Meiosis: nuclear division process that reduces the amount of chromosomes by 50%. This process produces 4 haploid cells (sperm and egg cells), which each contain 23 chromosomes.
Meiosis 1: during prophase of meiosis 1, the chromosomes pair up and swap sections of DNA (crossing over), which causes the chromosomes to contain genes from both parents.
Meiosis 2: is exactly like mitosis, except for the fact that the chromosomes aren’t duplicated again; in this process they line up and the sister chromatids are separated from one another.
Sex differences in meiosis: 4 sperm vs. 1 egg
Meiosis in males produces 4 equal sized sperm, but they each have their own genetic make-up (sperm have a small chance to reach an egg, so it is necessary for lots of sperm to be produced in the body). There is only one daughter cell produced during meiosis for females, and meiosis 2 isn’t complete until sperm penetrates the egg, once the sperm penetrates the egg their nuclei unite with one another.

Cell Reproduction Regulation
Cyclins: cyclic fluctuations in concentration of certain proteins that control the progression through the G1, S and G2 phases. These also activate certain regulatory proteins that initiate specific events within the cell (ex: DNA replication).
Cell Reproduction cycle can be stopped if certain nutrients aren’t available, if certain hormones aren’t present, or if grown factors aren’t supplied by other cells.
Environmental Factors that influence cell Differentiation
Differentiation: process by which a cell becomes different from its parent/sister cell; they begin to express different genes
Differentiation during Early Development: The cell divides by becoming 2 cells, then 4, then 8, then 16, etc. During the early stages (2 cells- 8 cells) all of the cells are exposed to the exact same environment; after you get to the 16+ cell stage then the cells on the outside of the “ball” are exposed to a different environment than those on the inside of the “ball”, they can be exposed to different amounts of oxygen (etc.) which could activate different genes, which in turn takes them on different paths of development.
Differentiation Later in Development: Each cell is shaped by 2 factors; its environment and the developmental history of the cells that came before it. Genes are turned off then on at certain stages of development, which causes the cells to differentiate from one another.
Cloning Organisms requires an undifferentiated cell
Reproductive Cloning: making copies of entire organisms- 2 types of reproductive cloning = embryo splitting & somatic cell nuclear transfer
Embryo Splitting: producing identical offspring: egg is fertilized in vitro and allowed to divide the 8-cell stage (before the differentiation can take place). Cells are then separated and each implanted into a surrogate mother; each of these cells will produce an exact genetic copy of all the others.
Somatic Cell Nuclear Transfer: Cloning an Adult: somatic cell= any cell in body except sex cell
Combines somatic cell from adult with an enucleated fertilized egg (the egg has no nucleus). The nucleus of the somatic cell from the adult has the instructions for making a copy of the adult and the enucleated egg carries out those instructions. An electric current is used to fuse the somatic cell and the egg together as one, the new cell that is produced represents the fertilized egg. The egg is then inserted into a surrogate mother and develops normally.
Therapeutic Cloning: Creating tissues and Organs
Therapeutic cloning= cloning of human cells specifically for treating patients. This type of cloning is aimed at taking either undifferentiated of partially differentiated cells from certain human embryos and cloning them for use in patients with specific disease. As of right now the best cells to use for this are embryonic stem cells, which is one of the reasons why there is so much controversy that surrounds this type of cloning.

Chapter 18- Cancer: Uncontrolled cell division & differentiation
2 key characteristics of NORMAL cells: they have regulatory mechanisms that keep their rates of cell division appropriately in check. They generally remain in one location throughout their lifetime (they adhere to their neighbors).
Tumors can be Benign of Cancerous
Hyperplasia= any substantial increase in the rate of cell division
In the normal cells progression towards cancer hyperplasia may be a signal of a loss of control over cell division.
Tumor= mass of cells that begin to divide at an abnormally high rate
Benign= remains in one single place, non-cancerous. They only threaten health if they become so large that they crowd normal cells.
Cancerous Cells lose control of their function/structures
When cells become cancerous their nucleus often becomes larger, the amount of cytoplasm is reduced and they lose their specialized functions and structures.
Dysplasia= abnormal changes in shape/function of cell. Often a sign that cells are “pre-cancerous”
Cancer: tumor is defined as cancer when some of its cells lose all semblances of organization, structure, and regulatory control. In Sutu cancer= tumor remains in one place.
Metastasis= spread of cancer to another organ/region of the body, caused by the cancer cells undergoing changes that cause them not to adhere to one another and form the tumor in a normal way. The cancer cells can break away from tumor and travel through blood stream and develop cancer sites in a different area of the body.
Malignant tumors= cancers that metastasize and cancers that invade normal tissues. Metastasizing cancer will continue to spread until it has completely taken control of all of the tissues, organs and organ systems.
How Cancer Develops
2 things must happen simultaneously: cell must grow/divide uncontrollably and cell must undergo physical changes that allow it to break away from surrounding cells.
Mutant forms of proto-oncogenes, tumor suppressor genes and mutator genes
Proto oncogenes= normal regulatory genes that promote cell growth, differentiation, division, or adhesion.
Oncogenes= mutated/damaged proto oncogenes that contribute to cancer. Some of them drive up the rate of cell division; others produce damage protein receptors, which in turn fail to heed inhibitory growth signals from other cells. One oncogene alone isn’t sufficient enough to cause cancer.
Tumor suppressor genes= regulatory genes that [under normal conditions] apply brakes to unchecked cell growth, division, differentiation, or adhesion. When they become damaged, they contribute to cancer because the activities that they usually regulate will go unregulated.
Mutator Genes= involved in DNA repair during the replication process. When these genes are mutated the cell becomes more prone to errors in the DNA replication.
Factors that Lead to Cancer:
Age: the cells become worn out and are less able to repair themselves when damaged, and mechanisms controlling cell division become less effective.
Genes: your parents could carry cancer promoting mutations within their cells which could be passed down to you. However, the fact that you could inherit these genes from your parents doesn’t guarantee that they could lead to you having cancer.
Carcinogens: any substance or physical factor that may cause cancer.
Viruses & bacteria: viral sequence of DNA may impair genes functions, perhaps inhibiting the regulatory gene from working properly. Viruses that can lead to cancer include HPV, Hep B & Hep C, and HIV.
Chemicals in the environment: they can directly damage the DNA, or sometimes merely their presence increases the potency of other carcinogens.
Tobacco: about 30% of all cancer deaths are contributed to this. Increases risk of cancer in lungs, mouth, pharynx, pancreas and bladder.
Radiation: sources include sun, and radioactive gas. Only account for appx. 2% of cancer related deaths. Melanoma= cancer of the melanin producing cells of skin (caused by high-frequency of UV B rays in sunlight)
Diet: can be involved in appx 30% of all cancers. Red meat and saturated animal fat raise risk of colon, rectum, and prostate gland cancers.
Internal Factors: free radicals= highly reactive fragments of molecules that are produced by the body’s biochemical processes. They’re normal by-product of the metabolism; if detoxification process in body becomes less efficient then these free radicals can accumulate and damage other molecules, including DNA. Antioxidants= certain vitamins the neutralize free radicals. (Ex= vitamins A, C and E).
Immune system in cancer prevention
When cells turn cancerous they no longer look like their original “self” and the immune system will naturally start to attack them. Stress, anxiety, depression and certain immunosuppressant drugs (such as HIV drugs) reduce the immune systems chance of fighting off the cancerous cells.
Early Detection
In 1971 President Nixon waged a war against cancer by signing the National Cancer act.
Tumor imaging: X-rays, Pet and MRI
Allow us to view changes that we could miss visually. They can show the differences between tissues that we can’t see with the naked eye. PET scans use radioactive substances to create a 3d image which shows the metabolic activity of body structures. MRI scans use magnetic fields to produce cross-sectional images of body structures. MRI is the only one that doesn’t expose the patient to radiation.
Genetic Testing
Genetic testing is controversial because in some cases people could test their genes for a disease that isn’t curable yet. It also is difficult to explain to patients that just because they have the mutated gene in their DNA it doesn’t guarantee that they will develop that particular disease.
Enzyme Tests
Telomerase is an enzyme that is most commonly found in cancer cells. Enzyme tests could be used to screen large populations or monitor the progression of the disease in patients.
Cancer Treatments
Most common treatments are surgery, radiation, and chemotherapy.
Chemotherapy: administration of cell damaging chemicals to destroy cancer cells. Some chemotherapy chemicals stop cells from duplicating by interfering with their ability to replicate DNA. These same chemotherapy chemicals can damage or kill normal cells that also divide rapidly such as bone marrow cells. The reason patients experience nausea during chemo is that the chemicals also damage their digestive tracks.
Magnetism and photodynamic therapy
Magnetism= they position a powerful magnet at the tumor site and inject metallic beads into the patient’s bloodstream. These beads are coated with a chemotherapy drug and the magnet pulls these beads into the tumor where these drugs kill the cancer.
Photodynamic therapy= targets cancer with light sensitive drugs and lasers. The drugs are drawn into the cancer cells, and then laser light is focused on the tumor where it triggers a series of chemical events that kill the malignant cells.
Attempts to boost the immune systems response so that it can fight off the cancer more effectively. They are trying to find specific antigens that are present on cancer cells but not normal cells so they can use those to produce antibodies.
“Starving” Cancer
Angiogenesis= growth of new blood vessels
Something within the tumor promotes angiogenesis, scientists are producing drugs that inhibit angiogenesis from taking place, and therefore the tumor wouldn’t be producing as many blood vessels and its energy level would rapidly decrease.
10 Most Common Cancers
Skin Cancer
Most common type= basal cell carcinoma; this occurs when basal cells divide out of control; it rarely metastasizes but should be removed. (Appears as pink/flesh colored bump)
Squamous cell cancer arises from epithelial cells; it can metastasize at a slow rate. (Appears as pinky scaly patches that can crust)
Melanoma is the least common of the 3, however it is the deadliest. It arises from abnormal melanocytes (dark patches/spots will appear on your skin)
Lung cancer
Most lung cancers are preventable, because the biggest cause is cigarette smoking. It can also be caused by exposure to 2nd hand smoke, radiation, or asbestos. Symptoms include persistent cough, recurrent pneumonia or bronchitis, and voice damage. Lung cancer is generally not detected early.
Breast Cancer
Usually only occurs in women. Generally diagnosed by a mammogram (x-ray of breast tissue). New research shows that there are 2 mutated genes (BRCA1 & BRCA2) that could lead to breast cancer. Major risk factor for this cancer is age; 1/26 women will get it in her 60’s, and 1/8 in her lifetime.
Prostate Cancer
Biggest risk is age; it is most common after you reach 50. Symptoms include difficulty urinating, inability to urinate, blood in urine and pain in your pelvic region. Treatment options include surgery, radiation therapy and hormones.
Cancer of Colon and Rectum
Signs include blood in stool or rectal bleeding. Risk factors include obesity, smoking, history of this cancer, low-fiber/high-fat diet. This cancer usually starts as polyps (small benign growths that develop on colon lining), these usually don’t turn malignant. Colonoscopy= examination of internal colon with a fiber-optic scope; recommended for everyone over the age 50.
Cancers of the lymphoid tissues, include Hodgkin’s disease and non-Hodgkin’s lymphoma. Symptoms include: enlarged lymph nodes, itching, weight loss, and night sweats.
Urinary Bladder Cancer
Blood in urine is a huge sign. Smoking doubles the risk of developing this. Surgery combined with chemotherapy is usually successful in beating cancer when it is detected early enough.
Kidney Cancer
Risk factors include: inherited gene mutations, smoking, exposure to asbestos and cadmium. There are no blood/urine tests to screen for renal cancer. Main treatment is removal of affected kidney.
Cancer of Uterus
Primary symptoms include abnormal bleeding or spotting. High lifetime exposure to estrogen is a major risk factor. Cervical cancer is strongly correlated to the STI called HPV. Treatments include surgery, radiation, hormone and chemotherapy.
Cancers of immature white blood cells within the bone marrow. In its later stages the production of normal cells decrease, which leads to anemia and reduced resistance to fighting off infections. Could possibly be linked to down syndrome, excessive exposure to ionized radiation and benzene. Symptoms include: fatigue, weight loss, increase incidence of infections. Standard treatment for this is chemotherapy.
Prevention of Cancers
Know your family history- cancer tends to involve multiple genetic defects, so you are more likely to have cancer if you have a history of it within your family.
Known your own body- if you even think you have suspicious lumps in your breast, strange changes in your skin, or are exhibiting any of the other signs of the other cancers then go see your doctor and get tested. You know your body best, so you know when something is wrong.
Get regular screenings- you can’t diagnose cancer if you don’t get checked for it. The longer you wait, the worse it could get and the less likely the treatments will be successful.
Avoid direct sunlight between 10am-4pm, where sunscreen with an SPF of 15+ or wear protective clothing.
Watch your diet and weight- general recommendation is a diet high in fruits, vegetables, legumes, and whole grains. Low in saturated fats, red meat, and salt.
Don’t smoke- it is considered the single largest preventable risk for cancer. It accounts for 85% of all lung cancers

Chapter 19- Genetics and Inheritance
Genome= sum total of an organisms’ entire DNA. Genetics= study of genes and their transmission from one generation to the next.
Your Genotype
Humans have 23 pairs of chromosomes (22 pairs of autosomes and then the pair of sex chromosomes). We inherit one of each pair of autosomes and one sex chromosome from each parent.
Alleles= alternative versions of genes that are produced when small differences in the DNA sequence exist between the pairs of autosomes. They may code for different proteins.
Homozygous- when a person possesses two identical alleles of a particular gene
Heterozygous- person who has two different alleles of a gene
Allele’s most likely result from millions of years of mutations of cells destined to become sperm/eggs.
Human Gene pool=all of the various genes and their alleles in the entire human population. There are enough alleles among our genes to account for the fact that each person is unique from one another.
Genotype= your complete set of alleles
Phenotype= your observable physical and functional traits. These include: hair color, skin color, eye color, height, and body shape (etc.). Phenotype is not only determined by your genotype, but also environmental factors such as how much you’re exposed to the sun, whether or not you exercise and where/what you eat.
Genetic Inheritance
Punnet square= simple way to represent patterns of inheritance of alleles and to predict which genotype will be inherited. You put the possible alleles of the male gamete on one axis of the 4 square grids, and the possible alleles from the female gamete on the other. Remember that although the parents are diploid they will only donate one of each chromosome to their offspring.
Mendel’s Basic Principle of Genetics
Gregor Mendel= an Austrian monk who specialized in natural history. Described the fundamental principles of inheritance through a number of controlled experiments involving breeding of garden peas. He followed the inheritance of traits such as flower color, pea color, and pea texture and plant height from one generation to the next. He concluded that these peas inherited 2 units of each factor (one from each parent); today we call these units genes, and we know that you get one gene from each parent.
Law of segregation: when gametes are formed in parents, the alleles separate from each other, so that each gamete gets only one of each gene.
Dominant alleles are expressed over recessive alleles
Dominant= allele that suppresses the expression of its complementary allele
Refers only to how an allele behaves in combination with a recessive allele in a heterozygote, it has nothing to do with the frequency of which the gene is found in a population.
Recessive= allele that doesn’t reveal its traits in the presence of a more dominant allele (2 recessive alleles must be present for its traits to be seen)
Most Recessive alleles originate as mutations at some point in our evolution and just remain in our human gene pool because they do no harm. However, some are the result of the absence of a functionally important protein (ex: cystic fibrosis afflicts only homozygous recessive individuals because their alleles no longer code for a specific essential protein).
2 trait Crosses
Mendel’s law of independent assortment: alleles of different genes are distributed to egg and sperm cells independently of each other during meiosis.
Other Dominance Patterns
Incomplete Dominance: Heterozygotes have an intermediate phenotype
Heterozygous genotype results in a phenotype that is intermediate between the 2 homozygous phenotypes. Example in Caucasians is the trait of having straight, wavy, or curly hair.
Products of both alleles are expressed equally. Example is the gene for blood type; the A and B alleles are codominant, so if an individual is heterozygous with an A allele and B allele then they will have blood type AB.
Sickle cell anemia= disease caused by one of 2 alleles involved in production of hemoglobin for red blood cells. One of the alleles codes for a hemoglobin molecule designated Hbs that differs from the normal hemoglobin molecule designated Hba. People homozygous for sickle-cell anemia (hbs hbs) have only one hbs hemoglobin in their red blood cells; oppositely people who are heterozygous for sickle-cell anemia (hba hbs) have equal amounts of each type of hemoglobin. If sickle-cell anemia is left untreated it can eventually lead to blindness, pneumonia, etc. However, the people who only have the sickle-cell trait rarely suffer from any symptoms. Sickle-cell anemia primarily affects Africans (and their descendants) and Caucasians of Mediterranean descent.
Other factors influence inheritance patterns and phenotype
Polygenic inheritance: phenotype is influenced by many genes
Polygenic inheritance= inheritance of phenotypic traits that depend on many genes. (Ex: eye color is controlled by at least 3 genes). Traits governed by polygenic inheritance are generally dispersed throughout the population evenly, with more people in the middle and fewer people at each end of the extreme.
Genotype and Environment affect phenotype
Ex of how environment affects the phenotype is how our diet affects our height and body size. Changes in height/weight have sometimes occurred within one generation, which is too quickly for it to be contributed by changes in the gene pool.

Environment can also lead to the development of certain disease. We tend to only inherit a slightly increased risk of developing a disease; our environment can further increase our risk and lead to the development of a disease. Ex: if your family has a history of heart disease due to high cholesterol then you can either lower your chances of getting the disease by controlling your diet and exercise, or you can increase your risk by an unhealthy diet and lack of exercise.
Linked alleles may or may not be inherited together
Linked alleles= alleles that are physically joined on the same chromosome. The closer they are to one another, the more likely they will be inherited together. They aren’t always inherited together though, due to cross-over which reshuffles alleles across each pair of autosomes during meiosis. How often linked alleles are inherited together is related to how closely they are to one another before and after all of the cross-overs take place. The avg. pair of chromosomes may have 2,000+ genes and crossing-over occurs about 30 times per pair of chromosomes, so linked alleles may start off fairly close to one another, but may end up far apart.
Sex-Linked inheritance: X & Y chromosomes carry different genes
Karyotype=composite display of the 22 pairs of autosomes arranged from longest to shortest, plus the sex chromosomes.
Depends on Genes located on Sex Chromosomes
The Y chromosome determines maleness (females have 2 x chromosomes; males have 1x and 1y). Males have a greater susceptibility for diseases associated with recessive alleles on the sex chromosomes.
Sex linked inheritance= refers to inheritance patterns that depend on genes located on the X or Y chromosomes.
It is X-linked if the gene is only located on the X chromosome. It is Y-linked if it is only located on the Y chromosome. Many genes on the X chromosome aren’t related to sex determination so there are many examples of X-linked inheritance. The Y chromosome is very small, and most of its traits relate to “maleness” so there aren’t many Y-linked traits.
Hemophilia is an example of an X-linked disease. Hemophiliacs lack a blood clotting factor that is encoded by an X-linked gene with 2 alleles. The recessive allele Xh is a mutant that cannot produce the clotting factor, whereas the dominant allele XH produces the clotting factor. You only get this disease if you don’t have at least one normal dominant allele.
Pattern that X-linked recessive genes follow:
More males have disease than females; females can be protected by inheriting at least one normal allele XH out of 2; whereas males inherit only one allele because they only inherit one X chromosome.
Disease is passed to sons solely through their mothers, even though the mothers may only be carriers (carriers are heterozygous), therefore they can pass on the recessive allele even though they don’t show any signs of it themselves.
A father cannot pass the disease to a son, but his daughters will all be carriers (unless the mother is a carrier too, in which case the daughters may have the disease).
Chromosomes may be altered in number or structure
Nondisjunction= failure of homologous chromosomes or sister chromatids to separate properly. This results in an alteration in the chromosome number of sperm/egg cells. Very rarely a piece of chromosome may break off or be lost, or it may reattach to another chromosome.
Down syndrome: 3 copies of chromosome 21
There are 3 types of Down syndrome, but 95% are caused by having 3 pairs of chromosome 21. Edward syndrome is caused by 3 pairs of chromosome 18, and patau syndrome is caused by 3 pairs of chromosome 13.
Traits of Down syndrome: people are typically short, have round faces, and most are friendly, cheerful, and affectionate. They tend to develop more slowly mentally, and have a higher risk of respiratory complications or heart defects. It affects about 1/1,000 live births in the U.S.
Risk for having child with Down syndrome increases with age. 1/1,300 in women younger than 30, 1/100 at age 40 and 1/25 for mothers over age 45.

Alterations of number of sex chromosomes
XYY-Jacob syndrome: males who tend to be tall but otherwise normal, however some show impaired mental function.
XXY- Klinefelter syndrome: also tall male phenotype. They can’t produce offspring, have mild mental impairment and may develop enlarged breasts (caused by extra X chromosome).
XXX- trisomy-x syndrome: usually female phenotype, have tendency towards mild retardation
XO- Turner Syndrome: individuals with only one X chromosome, usually female. Tend to be short with small breasts. Most aren’t mentally impaired in any way. They are however sterile.
Deletions & Translocations
Deletion= occurs when a piece of chromosome breaks off and then gets lost. Nearly all deletions are lethal to sperm and eggs; there are rare conditions in which a deletion of a chromosome still results in a live birth. Ex: cri-du-chat syndrome, deletion of chromosome 5, leads to mental and physical impairments and a small larynx.
Translocation= piece of chromosome breaks off but reattaches at another site, either on the same or a different chromosome. They result in subtle changes which alter their ability to function slightly
Many Inherited genetic disorders involve recessive alleles
You only express inherited disorders caused by recessive alleles only if they inherit two of the defective alleles. If you only inherit one defective allele you can pass the gene to your children, but they don’t get the disease themselves.
Homozygous recessive individuals are unable to make the enzyme that is needed for the normal metabolism of phenylalanine. If this amino acid accumulates it is used in other metabolic pathways and is converted into an acid that is toxic at high concentrations. Occurs in 1/12,000 births in Caucasians. Caused by mutation of gene on chromosome 1.
Tay-Sachs disease
Caused by recessive gene on chromosome 15. Individuals homozygous for the recessive allele are unable to make enzyme that is responsible for metabolism of a particular lipid. This lipid them accumulates in brain cells causing cerebral degeneration.
Huntington’s disease
Progressive nerve degeneration leads to physical/mental disability and death. Caused by a dominant lethal allele (dominant allele that actually causes a disease, in this case HD allele). This disease is fatal, with no known cure. Dominant lethal alleles are uncommon because they tend to eliminate themselves from the population.

Chapter 20- DNA Technology and Genetic Engineering
Biotechnology= field of applied biology that involves use of living organisms and bioprocesses in medicine, technology, engineering, and other fields
Recombinant DNA technology- field of applied biology that studies the applications of cutting, splicing, and creating DNA
Genetic engineering- manipulation of the genetic makeup of cells/organisms
DNA Sequencing reveals structure of DNA
First they start of by placing copies of single stranded DNA into a test tube. Then they add the primers (also single stranded pieces of DNA) into the tube and they bind to the end of the other strands of DNA. Primer serves as the beginning point for synthesis of a new DNA strand.
Next they add thymine (T), guanine (G), adenine (A) and cytosine (C), plus a mixture of T* A* G* and C* that have been modified so that as soon as one of them is added to the chain of DNA that is growing then further synthesis is stopped.
Finally they add the enzyme DNA polymerase that facilitates the addition of nucleotides one by one to the growing strand, and then the synthesis of DNA begins.
After the synthesis occurs the pieces are passed on a column of gel and subjected to gel electrophoresis. This creates an electrical field that causes the DNA pieces to migrate through the gel (smaller ones moving more quickly than the larger pieces). A computer detects the 4 different fluorescent labels as they come off the gel. Then a graphic display of nucleotides in the pieces (in order of size) is projected onto the computer.

DNA Can be cloned in the Laboratory
Recombinant DNA technology: isolating and cloning genes
Goal of this technology is to transfer pieces of DNA from one organism into another. It is most commonly used to insert specific genes into bacteria so that the bacteria can be induced to produce useful proteins.
Restriction enzymes- naturally occurring enzymes in some bacteria that break bonds between specific neighboring base pairs in a DNA strand. They protect bacteria from viral invasion by cutting up the DNA of the invading virus, but the will cut DNA from any source.
They are most useful for making a cut in palindromic double stranded DNA nucleotide sequences such as CTTAAG paired with GATTC (palindromic means they read the same way backwards and forwards). A cut in this type of sequence leave 2 short single stranded ends that are complementary to each other and also any other DNA that is cut with the same enzyme.
DNA ligases- enzymes that bind fragments of DNA back together after restriction enzymes have cut them.
Plasmids- small self-replicating DNA molecules found in bacteria. They contain certain genes needed for bacterial replication. They are also made to be able to incorporate a foreign piece of DNA.
Technique for producing recombinant DNA using human DNA
Isolate DNA plasmids and the human DNA of interest. The DNA of interest is isolated and purified; the DNA plasmids are prepared from bacteria.
Cut both DNAs with the same restriction enzyme.
Mix the human DNA fragments with the cut plasmids.
Add DNA ligase to complete the connections. Joins the plasmid and human DNA strands together.
Introduce new plasmid into bacteria.
Select bacteria containing human gene of interest and allow them to reproduce.
Cloning DNA fragments: The polymerase Chain reaction
Used to make millions of copies of small fragments of DNA, however they lack the regulatory genes and proteins required to activate genes.
In this process: first the strands of DNA are unwound, then they’re mixed with primers (complementary to one end of each strand), nucleotides (needed to create new complimentary strands), and DNA polymerase. The primers bind to the ends of the strands once the mixture is cooled, the primers rep the starting point of replication on the strands, the nucleotides attach to the growing complementary chain in sequence (with assistance of DNA polymerase).
Once the DNA is completely replicated, this process begins again and repeats itself, doubling the amount of the DNA each time.
DNA Fingerprinting
Technique used for identifying the source of a fragment of DNA after it has been sufficiently copied by PCR. Used in positively identifying suspects during a criminal investigation.
This technique takes advantage of 2 facts: 1) between useful genes in DNA are long repeating sequences of nucleic acids that code for nothing at all and 2) the lengths of these sequences are unique in each individual
They use the fragment of DNA that has been copied by PCR and use restriction enzymes to cut the DNA into pieces, the lengths of the repeating “junk” sequences are varied, these pieces are amplified by PCR and then labeled so they can be visualized. Then they’re subjected to gel electrophoresis (separating them according to size), and the printout that results is the DNA fingerprint.
This technique is also used in paternity testing, and to trace ancestral relationships.

Genetic Engineering Creates Transgenic organisms
Transgenic- organisms that have been genetically engineered so that they now carry one or more different genes from a different species
Transgenic Bacteria
Bacteria rapidly take up plasmids containing foreign genes because their reproductive cycles are so short, so they are one of the most commonly used organisms in genetic engineering
One of the most common uses of transgenic bacteria is to make essential human proteins, including hormones. Insulin is one of the most commonly produced hormones with this process.
These bacteria can also be used to create vaccines; the vaccines are made by injecting a weakened/killed version of the disease into a harmless bacterium. The goal is to get the bacteria to produce the surface antigen of the disease-causing organism.
Other common uses of transgenic bacteria are producing amylase, manufacturing citric acid and ethanol, and producing drugs for human use. They can also be used to clean up toxic wastes and oil pollutants.
Transgenic Plants
DNA of interest is inserted into a bacterium that infects plants. Once the bacterium is injected into the plant a few of its cells may take up the DNA laced plasmid, and a few of those may take up the recombinant DNA into their own genetic material.
This process has produced crops that grow faster (therefore produce more food), has made certain plants pesticide resistant (therefore allowing people to be able to spray pesticides on them to kill any insects that may have been harming them), it has also been used to produce foods with a higher amount of proteins/vitamins.
Scientists are also beginning to produce certain vaccines in these plants, and are now incorporating human genes and producing human proteins as well.

Transgenic Animals
Begins with inserting the DNA of interest into a fertilized egg, eggs is then replanted into a female for gestation.
This technique has been used in order to create stronger and faster growing animals (therefore raising the amount of animals for food production). These animals are also used to study specific human diseases. Ex: scientists have created mice that express the protein that causes Alzheimer’s in humans. Pharmaceutical companies are now using goats, sheep, and cows (they prefer larger animals) to insert genes that code for certain proteins because it’s possible to obtain the protein from the females milk.

Gene Therapy
Gene therapy- insertion of human genes into human cells to treat/correct a disease.
Must overcome Obstacles
It has proven difficult to insert the recombinant DNA into enough of the right type of cells because humans have trillions of cells.
Just because you are able to correct the genetic disorder in an individual, that doesn’t guarantee that that person still won’t pass that genetic disorder onto his/her offspring, unless they could insert the normal gene into the germ cells.
Vectors transfer genes into human cells
Retroviruses are the best class of vectors: they splice their own RNA-based genetic code permanently into the DNA of the cells that they infect. This makes them ideal for vector transfers, only as long as they are rendered harmless before they’re used.
Another method is to remove human cells from a target tissue, expose them to retroviruses containing the gene of interest, and then returning the cells into the patient from whom they came from.
Drawbacks of this technique: retroviruses only insert DNA into a cell when it is dividing, they could possibly disrupt the function of other genes.
Success with SCID
SCID= severe combined immunodeficiency disease
First patient treated for a disease was Ashanti Desilva in 1990. They used T cells isolated from her blood and grew them in the laboratory with a viral vector containing the gene for the ADA enzyme she lacked, and then the T cells were re-introduced into her blood stream where they began to produce the enzyme. One drawback was that she still needed regular doses of ADA because T cells have a small life span.

Outside Sources used
Chap 17
Cell cycle picture- March 1, 2012
DNA transcription- March 1, 2012
DNA replication- March 1, 2012
Mitosis/meiosis- March 1, 2012
Cloning- March 1, 2012
Chapter 18
Top 10 cancers- March 3, 2012
Chapter 19
Punnet squares- March 4, 201
Down Syndrome- March 4, 2012
Chapter 20
DNA Sequencing- March 6, 2012
DNA fingerprinting- March 6, 2012
Transgenic animals- March 6, 2012
Transgenic plants- March 6, 2012
Gene therapy- March 6, 2012

February 13, 2012


Filed under: Uncategorized — brewoods90 @ 12:29 am

Part 1: Milk
In the milk part of the lab, I will study the changes that occur in a small glass of milk, after leaving it out for a period of about 3-4 days.
I believe that as time passes the milk will begin to get a sour scent, as well as begin to curdle due to the evaporation of the water out of the milk after being set out for so long.
On Wednesday February 8th I poured half a cup of milk into a small cup and set it on top of my dresser in my room where I could check on the milk every morning after I woke up. After the first day passed not much change had occurred in the milk it didn’t have any type of bad scent and it was still in its liquid form. On the 2nd and 3rd days is when it began to get a slight stench to it, and it started to thicken and curdle.

At the end of the experiment the chunk of milk that had formed actually had a slight yellow ring around the outside of it, and the chunk of milk was setting on top of a small amount of water on the bottom of the cup that hadn’t evaporated out of it. The milk is curdled due to the lactic acid build up, which is caused by anaerobic cell respiration.

Milk on day one

Milk on final day

Part 2: Juice
In this part of the lab I will study what happens when you add a dark colored juice to three different cups of water all with different temperatures. The first cup will be a room temperature water, the second cup ice water, and the third cup will be boiling water.
I believe that after adding the juice to the room temperature water the juice will mix in and spread out in the water fairly quickly. I believe that after adding the juice into the ice water the juice will mix and spread more slowly because the juice molecules won’t be able to move as well in a low temperature. I believe that it will be the exact opposite for the boiling water because those molecules will be moving so quickly that I believe the juice will mix in with them in a faster time than the other two glasses.
After pouring the juice into the room temperature water I saw that the juice mixed in fairly easily and somewhat fast with the water.

After pouring the juice into the ice water I saw that it took longer for the juice to mix in and evenly spread throughout the water.

After adding the juice to the boiling water I found that the juice mixed in and evenly spread throughout the water at a pretty quick rate, much faster than the ice water, and a little bit more quickly than the room temperature water.

The juice had an easier time diffusing throughout the water with the higher temperature because the waters molecules were moving so much more quickly therefor the juice had no problem mixing in with them. It took the juice a bit longer to evenly diffuse throughout the ice water because those water molecules were moving at a much slower rate to it took the juice a while longer to evenly distribute itself throughout the water.

Room Temp Water

Ice Water

Boiling Water

Part 3: The Carrot
During this part of the lab, I will study the effects that placing a carrot into a fresh water solution and placing a carrot into a salt water solution over a 24 hour period.
I don’t believe that there will be much change in the carrot that is placed in the fresh water solution after only 24 hours, however I do believe that the one in the salt water may become a bit smaller [but not by much] after being in the cup for a 24 hour period.
I began the experiment by cutting off the end of 2 different carrots, measuring them and tying strings around the end that had been cut off. I then measured out two cups of water into two separate cups, and added a teaspoon of salt to one of the cups of water. Then I put one carrot into the freshwater cup and the other carrot into the salt water cup. The string seemed to be a bit tighter on the carrot than it had started out as well.
In the beginning the fresh water carrot measured to be 2 inches long and ¾ inches wide, after being in the freshwater solution for 24 hours I was shocked to find that the carrot had actually gotten a little bit larger, it was now 2 1/5 inches long and 1 just shy of 1 inch wide. It also seemed to have gotten more firm after being in the freshwater for a day.
In the beginning the salt water carrot had measured 2 inches long and ½ and inch wide. After being submerged in the saltwater solution for 24 hours it had actually shrunk a bit, and was now 1 and ¾ inches long and about 2/5 inches wide. The string was slightly loose on the carrot after a day of submersion, but not by much.

The Freshwater carrot had swelled up because it was submerged it what is called a “hypotonic” solution, which caused the water to diffuse into the cells of the carrots, which in turn caused them to swell up.
The Salt water carrot had slightly shrunk because it was placed into a “hypertonic” solution, which caused the water inside of the cells of the carrots to diffuse into the surrounding solution causing the cells of the carrots to shrink.

Fresh Water on the left, Salt water on the right

Fresh Water carrot on left. Salt water carrot on the right.

February 10, 2012

Filed under: Uncategorized — brewoods90 @ 3:11 am

Unit 1 Compilation (Chapters 1-4)

Chapter 1
Characteristics of Life-
All living things are composed of cells (unicellular= one cell, multicellular = composed of many different cells). They all require energy- metabolism= chemical/physical process that occurs in cells in which the cell transforms food (etc.) into energy and gets rid of wastes. They all maintain homeostasis: they must maintain a constant internal environment for all of their cells (etc.) to function properly. All living things respond to the stimuli in their external environment; ex: if your body is too hot you’ll start to sweat in order to maintain your body temp. All living things can reproduce, and evolve over generations.
Classification of Organisms-
5-kingdom classification system: Monera: consists of all single celled prokaryotic (no nucleus) organisms and combines all bacteria into one kingdom. Animalia: multicellular, get their energy from consuming other organisms. Plantae: multicellular, can’t move, use sunlight and the process of photosynthesis to get their energy. Fungi: multicellular, absorb nutrients from other organisms. Protista: mostly unicellular and simple multicellular organisms, eukaryotic (have a nucleus); animals, plants and fungus are believed to have evolved from the Protista kingdom.

Humans are part of the animal kingdom classified as vertebrates and sub classified as mammals. Humans have defining features which include; Bipedalism: meaning we walk standing upright and on two feet, Opposable thumbs: meaning our thumbs can be worked in a way where they can touch the tips of each individual finger, which gives us more control over the objects we pick up, Humans have large brains: some argue it is due to the use of tools and some argue that it was developed because it was necessary for our language and interactions with one another. Humans have capacity for complex language we not only use verbal language, but also signs and body language as well to communicate with one another.
Levels of biological organization
(From smallest to largest) Atoms, molecules (made of more than one atom), Cells (smallest units of life), Tissue (group of cells with same function), Organ (group of tissues with same function), Organ System (two/more organs working together for same function), Organism (living being composed of many organ systems), Population (group of same species living within the same area), Community (several different species who live in same area), Ecosystem (all living and nonliving organisms within the same area), Biosphere (every ecosystem combined).

Chapter 2
-Matter & Elements
Matter= anything that occupies space, and is composed of elements = makes up matter and can’t be broken down to a simpler form. Atoms= smallest part of element that still retains the same physical/chemical characteristics of that element. Parts of atom are: Nucleus (central core), protons (positively charged particles), neutrons (neutral particles) and electrons (negatively charged particles) which set in “shells” around the nucleus. (Shells can only accommodate certain # of electrons; inner most only holds two, 2nd & 3rd can hold eight). Protons are usually equal to the number of neutrons. Isotopes = atoms with more/fewer # of neutrons than the usual number for that element. Living organisms mainly consist of 6 main elements; oxygen, carbon, hydrogen, nitrogen, calcium & phosphorous.
Molecule= a stable association between two or more atoms. Energy= capacity to “do work”. Joining and breaking up molecules both require energy. Potential energy=stored energy that isn’t doing any work at the moment. Kinetic energy= energy that is actually doing work at the moment. Potential energy is stored in bonds that hold atoms of molecules together. When the chemical bonds between those atoms of molecules are broken then kinetic energy is released.
-Types of Chemical Bonds
Covalent= when atoms share electrons between one another in order to fill up their outer most “shells”, this is the strongest type of chemical bond. Ionic bond= formed between the bond of oppositely charged ions (ions= electrically charged atom/molecule), the atom either gives up or completely takes electrons. Hydrogen bond= forms between hydrogen atom with a slight positive charge and any nearby atom w/ a slight negative charge; this is the weakest of the bonds.
-Importance of Water
It is a biological solvent, which means other substances dissolve in it, many chemical reactions are able to take place in it because of this, and it can also flow freely through the body making it ideal to transport solutes. It helps regulate our body temperature; it can absorb/hold a lot of heat and energy with very little to no change in its temperature, when we sweat and the water is evaporated off of our body it helps to cool us down.
-Importance of Hydrogen Ions
Acid= any molecule that can give up a hydrogen ion. Base= any molecule that can accept a hydrogen ion. pH scale= measure of the concentration of hydrogen ions in a solution. It ranges from 0-14, 7 is the ideal pH, anything less than 7 is said to be “acidic” anything over 7 is said to be “alkaline” or more “basic”. Buffers= substances that help to minimize the change in the pH level, these are essential to help us in maintaining homeostasis.

-Organic Molecules
Organic molecules= contain carbon and other elements that are held together by covalent bonds. Carbon accounts for approximately 18% of human body weight. Macromolecules = type of organic molecule formed by dehydration synthesis (2 smaller molecules join together using a covalent bond and remove the equivalent of a water molecule). The synthesis of macromolecules requires energy, which is why we need energy to survive/grow. Organic molecules are broken down into smaller molecules by using a process called hydrolysis (covalent bonds are broken and equivalent of a water molecule is added to the molecule). 4 classes of organic molecules that are synthesized by living organism are Carbohydrates, lipids, proteins, and nucleic acids.
Used for energy or structural support. Monosaccharide= simplest type of carb, ex: ribose, glucose, and fructose. Oligosaccharide= short strings of monosaccharide’s linked together by dehydration synthesis, ex: sucrose and lactose. Polysaccharides= thousands of monosaccharides are linked together by dehydration synthesis, they help cells to store any extra energy in the bonds between their molecules; ex: glycogen and starch.

Relatively insoluble in water. Triglycerides= synthesized from glycerol molecule formed with 3 fatty acids, these help to store energy. Phospholipids= modified lipids, they are the primary structural component of cell membranes. Steroids= made up of four different rings (three 6 membered carbons and one 5 membered carbon), ex: cholesterol.
Proteins= macromolecules that consist of over 100 amino acids linked together. Polypeptide= string of 3-100 amino acids. They have many different functions: Including structural support, muscle contraction and formation of the cell membrane. Denaturation= permanent disruption of protein leading to its loss of biological function. Enzyme= protein that functions as a biological catalyst (speeds up rate of chemical reactions without itself being altered). Enzymes help biochemical reactions to occur without changing the final result, homeostasis is important for helping enzymes to maintain their proper shape and biological activity.
-Nucleic Acids
Ex: DNA and RNA. DNA directs everything the cell does; RNA is responsible for carrying out the instructions of DNA.
Universal energy source for cells; the bonds between the phosphate groups in them contain a large amount of potential energy.
Chapter 3
-Cell Doctrine
1) All living things are composed of cells and cell products. 2) Single cell= smallest unit that exhibits all characteristics of life. 3) All cells are made from pre-existing cells.
-Cell Classification
Eukaryotes= have plasma membrane (outer membrane of cells that help to contain all the material inside the cell), nucleus, cytoplasm and organelles; human cells are eukaryotes. Prokaryotes= have no nucleus, and lack most organelles; ex= bacteria (monera kingdom).
-Cell structure reflects the function
Muscle cells contain many mitochondria which help form energy for contractions. Nerve cells tend to be long and thin which help them to transport impulses more quickly. Cells that line kidneys are cube shaped and held closely together which helps in transporting water. Cells are small because it helps them to remain efficient, the smaller the cell the more efficiently it can obtain materials and get rid of wastes. *Plasma membrane- regulates what gets into and out of cells and helps to transfer information from one cell to another; made up of phospholipids, cholesterol and proteins.
-Ways molecules cross the plasma membrane
Passive transport= transports molecules without using any of the cell’s energy (the cells move down their concentration gradient); ex: diffusion= movement of molecules from one region to another, molecules tend to move from areas of high-to-low concentration; osmosis= diffusion of water across a selectively permeable membrane; Facilitated transport= molecule attaches to a membrane protein and then the protein changes shape and transfers the molecule to the opposite side of the membrane.
Active transport= requires energy, it can move substances through the plasma membrane against their concentration gradient (they can move from low-to-high concentration). Helps cells to accumulate essential molecules and get rid of ones they don’t need. Proteins that actively transport molecules are called “pumps”.
Endocytosis= moves large materials into the cell. Exocytosis= moves large materials outside of the cell.
Receptor proteins= span across plasma membrane and can receive/transmit information across the membrane.
-Cell Structures
Nucleus= information center of cell, contains most of cell’s DNA. Ribosomes= composed of RNA, they’re responsible for making specific proteins. Endoplasmic reticulum= synthesize most of the chemical compounds made by the cell (rough ER has ribosomes on it and helps synthesize proteins, smooth ER doesn’t have ribosomes attached and helps synthesize other types of macromolecules). Golgi apparatus= receives substance from the ER, refines them, and packages them into vesicles. Vesicles= membrane bound spheres that enclose something within the cell (lysosome= digest bacteria and remove damaged mitochondria, secretory vesicles contain things that need to be exported from the cell, they release these things by exocytosis). Mitochondria= responsible for providing most of the usable energy needed by cell, manufacture ATP as needed. Cytoskeleton= attach to and help to support the cell’s plasma membrane (consists of microtubules and microfilaments). Cilia/flagella= (cilia are shorter) extend from surface off membrane and help the cell to move.

Chapter 4
-Epithelial tissue
Sheets of cells that line/cover certain body surfaces and cavities. They help to protect underlying tissues, they are often smooth to reduce friction, they absorb water/nutrients, also secrete waste products across kidney tubules. Glands= epithelial tissues that are specialized to synthesize/secrete a product. Exocrine glands= secrete their products into a hollow organ/duct, endocrine glands= secrete hormones into blood stream. Basement membrane= directly beneath cells of epithelial tissue, it is a non-cellular layer that provides support.
-Connective Tissues
Supports the softer organs of the body against gravity, and connects parts of the body together, also stores fat and produces blood cells. They have few living cells and they mostly consist of nonliving extracellular material called the matrix.
-Muscle tissue
Consists of cells that are specialized to shorten, or contract resulting in some type of movement. Composed of tightly packed cells called muscle fibers. Skeletal muscle= connect to tendons, which attach to bones. When they contract they cause body parts to move. Cardiac muscle= only found in heart, only have one nucleus, they’re short and have gap junctions between them which help them to send electric signals between one another so they contract in a coordinated fashion. Smooth muscle tissue= surrounds hollow organs and tubes, only have one nucleus, they have gap junctions between the cells so when one contracts nearby cells also contract.
-Nervous tissue
Consists primarily of cells that are specialized for generating/transmitting electrical impulses throughout the body. Neurons= nervous tissue cells that generate and transmit electrical impulses. This tissue forms a rapid communication network for the body.
-Organ Systems

Works Cited February 9, 2012 February 9, 2012 February 9, 2012 February 9, 2012 February 9, 2012

January 28, 2012

Filed under: Uncategorized — brewoods90 @ 6:29 pm

My name is Breanna, I’m 21 years old and I have a 2 year old daughter named Annabelle who means the world to me! Right now I work as a customer service supervisor at Interstate Autoglass; I love my job and my coworkers so I can’t really complainn! I’m finishing up my MA certification and taking all of the radiology prerequisites through Yavapai right now. I hope to one day be a radiation therapist at a children’s hospital because i absolutely love working with children! My life isn’t really all that exciting in most people’s eyes; I just work, go to school and hangout at home with my family! But i love every minute of my life and wouldn’t change a thing!

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