Chapter 8.txt

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Chapter 8.txt
2011-01-03 01:18:04
AP Biology

Chapter 8
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  1. acetyl-CoA
    Coenzyme A bound to a twocarbon fragment from pyruvate, which it transfers to oxaloacetate for Krebs cycle.
  2. aerobic respiration
    [Gk. aer, air, + bios, life] Oxygen-requiring pathway of ATP formation in mitochondria: from glycolysis, to Krebs cycle and electron transport phosphorylation. Typical net energy yield: 36 ATP per glucose molecule.
  3. alcoholic fermentation
    An anaerobic ATPforming pathway using pyruvate and NADH from glycolysis. NADH transfers electrons to an intermediate, acetaldehyde, forming ethanol. Occurs in cytoplasm only. The net yield is 2 ATP from glycolysis; the steps remaining only regenerate NAD+.
  4. anaerobic electron transfers
    [Gk. an, without, + aer, air] Of some bacteria and archaeans, ATP formation by way of a flow of electrons through transfer chains in the plasma membrane to a final electron acceptor that is not oxygen.
  5. ATP
    Adenosine triphosphate. A type of nucleotide that functions as the main energy carrier between reaction sites in cells. Consists of the base adenine, the five-carbon sugar ribose, and three phosphate groups.
  6. ATP synthase
    A type of membrane-bound active transport protein that also catalyzes the formation of ATP.
  7. coenzymes
    An organic molecule that is a necessary participant in some enzymatic reactions; helps catalysis by donating or accepting electrons or functional groups; e.g., a vitamin, ATP, NAD+.
  8. electron transfer phosphorylation
    Final stage of aerobic respiration; electron flow through electron transfer chains in inner mitochondrial membrane sets up H+ concentration and electric gradients that drives ATP formation. Oxygen accepts electrons at the end of the chain.
  9. FAD, FADH2
    Flavin adenine dinucleotide. A type of nucleotide coenzyme; transfers electrons and H+ from one reaction site to another.
  10. glycolysis
    Breakdown of glucose or another organic compound to two pyruvates. First stage of aerobic respiration, fermentation, or anaerobic electron transfer. Oxygen has no role in glycolysis, which takes place in the cytoplasm of all cells. Two NADH form. Net yield: 2 ATP per glucose molecule.
  11. Krebs cycle
    The second stage of aerobic respiration in which many coenzymes form as pyruvate from glycolysis is fully broken down to CO2 and H2O. Two ATP also form. Occurs only in mitochondria.
  12. lactate fermentation
    One of the anaerobic pathways of ATP formation. NADH from glycolysis donates hydrogen and electrons to pyruvate, converting it to three-carbon lactate, and regenerating NAD+. The net energy yield is 2 ATP (from glycolysis).
  13. mitochondrion
    Double-membraned organelle of ATP formation; only site of the second and third stages of aerobic respiration.
  14. NAD+, NADH
    Nicotinamide adenine dinucleotide. A nucleotide coenzyme; after it accepts electrons and H+, abbreviated as NADH.
  15. oxaloacetate
    A fourcarbon compound with roles in metabolism; e.g., the point of entry into the Krebs cycle.
  16. PGAL
    Phosphoglyceraldehyde. During glycolysis, the intermediate that gives up electrons and hydrogen to form NADH. During turns of the Calvin´┐ŻBenson cycle, two PGALs form one sugar; rearrangements of ten others regenerate a compound that is the entry point for the cycle.
  17. pyruvate
    Three-carbon compound that forms as an end product of glycolysis.
  18. substrate-level phosphorylation
    Direct, enzyme-mediated transfer of a phosphate group from a substrate to another molecule.