<p>Since an AP US thread has been created, we might just as well have a biology one. I think this is a great way to review the material. This thread will be a virtual study group.</p>
<p>Ok, I'll start.</p>
<p>Q: What is the difference between allopatric and sympatric speciation?</p>
<p>allopatric geographic barrier
sympatric - no geographic barrier</p>
<p>this can lead to species...</p>
<p>Isolation, Mutation, etc.</p>
<p>Q: Name a few causes of genetic diversity.</p>
<p>natural selection, genetic drift, founder effect, migration, mutation, population bottlenecks</p>
<p>Explain the parts/function of the nervous system. (central/peripheral, somatic/autonomic etc.)</p>
<p>Peripherial - passageways for impulses+sensors
Central - pretty much everything else
Somatic - volountary control/skeletal muscles
Autonomic - involountary/organs and glands</p>
<p>Q: where is hormon melatonin produced and what does it do?</p>
<p>Melatonin is an amino acid derived hormone produced in the pineal gland which induces sleep. (Dark stimulates its secretion while light inhibits it) It plays an important role in circadian rhythm regulation.</p>
<p>Q: Explain Hamilton's Rule.</p>
<p>First off this thread looks dead so im going to try and resuscitate it.</p>
<p>Hamilton's rule is basically this equation R x B > C.
it was the first formal quantitative treatment of kin selection( a mode of natural selection that acts on an individual's inclusive fitness or in other words survival of the fittest) to deal with the evolution of apparently altruistic acts.
R = the genetical relatedness of the recipient to the actor, usually defined as the probability that a gene picked randomly from each at the same locus is identical by descent.
B = the additional reproductive benefit gained by the recipient of the 'altruistic' act,
C = the reproductive cost to the individual of performing the act. </p>
<p>Information found at
<a href="http://en.wikipedia.org/wiki/Hamilton's_rule#Hamiltons_Rule">http://en.wikipedia.org/wiki/Hamilton's_rule#Hamiltons_Rule</a></p>
<p>What is produced in Photosynthesis and how much is produced?</p>
<p>Photosynthesis :</p>
<p>6CO2 + 6H20 + light ----> C6H12O6 + 6O2</p>
<p>Describe the passage of deoxygenated blood from the body through the heart/lungs and back to the body.</p>
<p>Capillaries - Venules - Veins - Superior and Inferior Vena Cava - Right Atrium - Right Ventricle - Pulmonary Artery (splits into left and right) - Pulmonary Vein - Left Atrium - Left Ventricle - Aorta - Arteries - Arterioles</p>
<p>Describe the difference between C3, C4, and CAM photosynthesis</p>
<p>anyone know any good ap psych books?</p>
<p>C3 photosynthesis is the most common form of photosynth. Light hits the different photosystems/chlorophyll pigments, and the energized electrons jump up to an electron acceptor which forms an electron transport chain. A bunch of other steps go on including photolysis and phosphorylation, but the basic products are NADPH and ATP. Then the Calvin Cycle takes over, making the CO2 combine with RuBP forming PGA using the enzyme rubisco (RuBP carboxylase). ATP and NADH are used to make 12 PGAL from 12 PGA. Then, 6 ATP are used to convert 10 of those PGAL back into RuBP so the cycle can continue. The two remaining PGALs are used to build glucose <-- energy storing molecule. </p>
<p>C4 is similar, but basically more efficient at fixing CO2 because it decreases photorespiration (wasteful process where plant fixes O2, an evolutionary relic) by using a different enzyme (PEP Carboxylase) than rubisco and by moving the CO2 to the bundle sheath cells (oxygen doesn't reach here so photorespiration is cut down). Since C4 plants are more efficient in fixing CO2, they have more energy and don't need to open stomata as often to get more CO2. C3 plants need more CO2 since they're not as efficient; opening stomata gives them the CO2 but also forces them to give off water. Since C4 plants make most of their CO2 they don't need to open their stomatas as much and thus conserve water.</p>
<p>These plants tend to be in dry, hot climates like deserts.</p>
<p>CAM photosynthesis stands for crassulacean acid metabolism, and the main difference here is that the plants fix CO2 into malic acid at NIGHT, thus reducing H2O loss since nighttime is usually cooler/less chance of drying out. Malic acid is shuttled to the vacuole. Then, during the day, the malic acid is converted back into oxaloacetic acid, releasing the stored CO2. CO2 is fixed by rubisco and Calvin Cycle proceeds. The main advantage here is again preservation of water by doing part of the photosynthesis at night. </p>
<hr>
<p>Explain how chemiosmosis works in mitochondria.</p>
<p>Okay...let's ressurect this thread. </p>
<p>The energy released as electrons pass down the gradient from NADH to oxygen is harnessed by three enzyme complexes of the respiratory chain (I, III, and IV) to pump protons (H+) against their concentration gradient from the matrix of the mitochondrion into the intermembrane space. As their concentration increases there (which is the same as saying that the pH decreases), a strong diffusion gradient is set up. The only exit for these protons is through the ATP synthase complex. As in chloroplasts, the energy released as these protons flow down their gradient is harnessed to the synthesis of ATP. The process is called chemiosmosis and is an example of facilitated diffusion.</p>
<p>Q: Discuss the parts of the brain and what they do.</p>
<p>Cerebrum - In control of voluntary activity and receives/interprets sensory info</p>
<p>Hypothalamus - Regulates homestatsis and secretes hormones</p>
<p>Cerebellum - Coordinates muscle activity</p>
<p>Medulla - It contrals the involuntary acctions such as breathing and swallowing (basicaly opposite of cerebrum)</p>
<p>Describe the enzyme-substrate reaction process</p>
<p>An enzyme binds to a specific substrate that is built like a key for that spec. substrate</p>
<p>The substrate changes a bit of shape to allow in the enzyme</p>
<p>However, if an inhibitor (competitive=taking enzymes's spot, noncomp=binds to another part of substrate) is involved, the enzyme does not function</p>
<p>Which phase of cellular respiration probably evolved longer ago than the others?</p>
<p>Glycolysis - Since the Earth's atmosphere lacked oxygen in earlier times, it makes sense that an anaerobic process would evolve first.</p>
<p>(I think)</p>
<p>Describe the different kinds of organismal behavior/response (habituation, imprinting, classical cond, etc.)</p>
<p>It took me so long to write my answer to Hermione's enzyme question that two people posted before me haha... here's what I wrote, so that I don't feel like I completely wasted my time....</p>
<p>Enzymes are organic catalysts; they lower the amount of activation energy needed for a specific chemical reaction to occur. </p>
<p>How it works: The regions of charge of the substrate (the reactant an enzyme acts on) are complimentary to the active site of the enzyme. The active site is a restricted region of the enzyme, typically a pocket or groove, formed by only of a few of the enzyme's amino acids. When the substrate enters the active site, the enzyme changes its shape very slightly in order to fit more snugly aroudn the reactants; this is called an induced fit. The induced fit allows chemical groups of the active site to more efficiently catalyze the chemical reaction. </p>
<p>The union of the substrate and active site is called an enzyme-substrate complex. The enzyme and substrate are usually held together by ionic or hydrogen bonds. Side chains of the active sites amino acids catalyze the conversion of the substrate to the product. The product leaves the active site, which is then free to take on more substrate molecules.</p>
<p>The active site manages to lower the reactions activation energy by distorting the substrate, stretching and bending the critical chemical bonds that must be broken for the reaction to occur. In some cases, the active site provides a microenvironment that is conducive to a certain type of reaction (such as one that requires an acidic environment). In other cases, the active site will briefly form a covalent bond with the substrate, but subsequent steps restore the active site to its orignal structure.</p>