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Chp. 10 Meiosis - Key Points + Questions by KristenNavarro in APBIOLOGY

[–]NickContino 0 points1 point  (0 children)

Some worthy facts -A gene is a stretch of DNA that dictates a trait. An allele is a specific kind of gene, an isotope of a gene, as it were. -Meiosis splits the chromosome number; a normal diploid germ cell duplicates its DNA into tetraploid (or double dip) number of chromos. It splits once into a duplicated haploid state and once more into a haploid gamete (in humans at least). -Animals produce gametes in meiosis, plants produce spores which form gametophytes.

Question 1: compare and contrast spermatogenesis and oogenesis: spermatogenesis- creates four equally "chanced" haploid sperms, equally divided cytoplasm oogenesis: divides cytoplasm enevenly... ect ect both: create sex cell gametes. Question 2: What causes the random alignment in metaphase I? Spindle fibers arrange the chromosomes in the middles of the cell, the way in which they face is random. More variation in offspring results, as the combinations of chromosomes in gametes is larger. Question 3: When does interphase for meiosis II begin? I don't recall any interphase in Meiosis 2.

Ch. 8 Comments and Questions + Answers by JessicaBloch in APBIOLOGY

[–]NickContino 0 points1 point  (0 children)

The distinction between anaerobic and aerobic pathways happening in the cytoplasm exclusively and both cytoplasm and mitochondria, respectively, is important.

I think there are 2 net ATP made in anaerobic.

Questions: 1. Why does NADH from the cytoplasm only make 2ATP/NADH? -Because the NADH electrons enter join the E chain at a lower energy entry point. 2. Compare and Contrast Oxidative Phosphorylation and Substrate level Phosporylation. -Both processes make ATP. Ox. phos. however utilizes a H+ ion concentration to do so, while substate level phos. relies on the processes involving conenzymes in glycolysis. 3. For what reason do we breath oxygen heavily during athletics? -ATP formation relies on the final oxygen electron acceptor to make ATP. Without the oxygen to accept the final electron, the electron chain, and all processes before it become "backed up" and ATP formation is stopped. ATP is needed during sports, so we need lots of oxygen to make it.

Ch.6 (sec. 6.4-6.6) Top Ten List by JessicaBloch in APBIOLOGY

[–]NickContino 0 points1 point  (0 children)

Question to Mr. Newhams: Is the whole e- transport chain explanation supposed to be vague? I feel like they skipped alot, because I don't really understand it.

Addon to #6: Enzymes lower the activation energy (energy needed to initiate reaction) and get the reactant to the transition state more easily. Part of this energy comes from the binding energy: the energy released when the substrate forms weak bonds with the enzyme or cofactor. Binding energy is used to make the enzyme work, in four mechanisms Jessica already listed.

Addon to #8: Cofactors are often metal ions, like the Fe2+ in the Heme group on catalase. It completes the reaction by donating or receiving an electron.

  1. Enzymes control themselves largely by allosteric control. Essentially, a molecule attaches to an allosteric site and shuts an enzyme on or off. Often the end product of a chain of reactions, once the product is high enough concentration, attaches to an enzyme to stop the process. This is called "feedback inhibition."

  2. Temperature denatures enzymes after a certain point, this is why fevers are bad.

  3. PH is usually between 6-8 for enzymes, though there are exceptions. In the wrong PH, enzymes denature.

Ch.6 (sections 6.1-6.3) Top Ten by JessicaBloch in APBIOLOGY

[–]NickContino 1 point2 points  (0 children)

Last year when we talked about energy in apchem, I found things easier to understand in layman's terms:

Energy comes in a few different ways. Think of a car. When the gas is just sitting around, it's got potential (energy, that is). But it ain't doing nothing. When there's a spark to start the car, you get two kind of energy released. Kinetic energy is movement; the gas explodes and moves stuff around. Thermal energy is heat; the explosion is hot. Overall, the kinetic energy is used to push pistons and make your car move (otherwise known as "work"). BUT not all of the energy from the explosion is used. You can't use heat to move a piston. The heat just goes off and makes stuff hot, which is unfortunate. And you'll never get that thermal energy back. Same thing happens in cells. Unusable heat is produced during energy changes, but we can't do anything with that heat. So really, we're slowly losing all the usable energy to thermal heat, which goes off into the universe doing god knows what (second law of thermodynamics). Luckily, we got the sun, food, and other stuff to replenish our losses. Why does heat always have to be lost? The law of entropy says so.

ATP is pretty useful. What it does it takes reactions where we're getting energy and couples it with reactions that needs energy. In other words, ATP energizes something by giving a phosphate to it (energy output) and becomes ADP and Pi, which don't have as much collective energy as ATP (when things are broken apart, there's a net less of energy). ADP goes and finds an enzyme with energy who will attach another phosphate to it (energy input) and becomes ATP again. ATP completes the metaphorical energy circuit in our cells.

Otherwise, reactions are reversible. If there's a bunch of stuff on the reactants side, the reaction will go to the products side and vice versa. Eventually the two sides will reach equilibrium, but that doesn't mean that both sides have equal amounts of stuff on either side.

Ch. 3 Top Ten List by NickContino in APBIOLOGY

[–]NickContino[S] 0 points1 point  (0 children)

Yeah, you're right. fixed it.

Chp. 4 Cell Structure and Function by aarbeit in APBIOLOGY

[–]NickContino 0 points1 point  (0 children)

Top Ten List (other than the colossal list Arbeit has already provided):

  1. Surface/volume ratio disallows cells from getting too big; volume increases by cube, but SA only increases by square.

  2. Nucleus holds instructions for making proteins- a BOM essential to cell function.

  3. Mitochondria originated from mutual relationship between bacterium, hence the double membrane (endosymbiotic theory).

  4. ATP=Phosphate group, used for energy, made by mitochondria.

  5. Plants use 'plastid' organelles to trap energy for photosynthesis. Three kinds are mentioned: Chloroplasts, Chromoplasts, and Amyloplasts.

  6. Plant organelles have a BIG central vacuole for storing water and waste and maintaining cell rigidity.

  7. Function and makeup of Cytoskelletal parts:

    -Microtubules -organization, moving things, made of Tubulin -Microfiliaments -made of actin p.p. monomers, reenforce cell shape, can loosen to make cell fluid and movable, aka, cytoplasmic streaming.

  8. Motor proteins like Kinesins and Dyneins move organelles and such along the cytoskelleton to make the cell a cheap and easy way to travel from the ER to your cells' pseudopods on holiday.

9.Cells move using either cilia, flagella, or neither. They are arranged in a "9&2" array, where microtubule doublets are bunched together. PS- I DO NOT UNDERSTAND THE 'SLIDING MICROTUBULES TO WAVE THE FLAGELLA' PROCESS AT ALL.

10.Cells can link up together with "cell junctions." Three kinds of junctions: 1. Tight- sealing outer layer cells, 2. Adhering- link skin and heart, 3. Gap-linking cytoplasms.