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12 Cards in this Set
- Front
- Back
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The Nature of Chemical Energy |
~ Electronsare the most important source of chemicalpotential energy inbiology. ~Covalent bonds = electrons with energy in them. ~Electrons closer to other electrons andfarther from nuclei of atoms, have higher potential energy. |
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Electronegativity |
•Cand H havesimilar electronegativities •Oand N havehigher electronegativity than C or H and they tend to hog the electrons! •Abond between unequal atoms = more stable •Abond between equal atoms = less stable |
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Electronegativity: NAD (Nicotinamideadenine dinucleotide) |
~ is reduced to form NADH. ~ NADHreadily donates electrons (& H+) toother molecules and is thus called an electroncarrier andhas “reducing power.” |
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The Steps of Cellular Respiration: Step 1 |
~ Glycolysis - glucose is broken down to pyruvate. - happens in the cytosol - Energy spent (1 Glucose) ~ Remaining rxn occur in the mitochondria - The pyruvate is transported into themitochondria.• - All the NADH heads over to themitochondria also. |
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The Steps of Cellular Respiration: Step 2 |
Pyruvate processing - pyruvate is oxidized to form acetylCoA. - Happens in mitochondria |
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The Steps of Cellular Respiration: Step 3 |
Citric acid cycle - acetyl CoA is oxidized to CO2. - lots of NADH & FADH2 |
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The Steps of Cellular Respiration: Step 4 |
Electron transport (the chain) ~ Chemiosmosis ~ Compounds that were reduced in steps1–3 are oxidized in reactions leading to ATP production. ~The ETC pumpsprotons fromthe mitochondrial matrix to the intermembrane space or the interior of cristae. ~ The proton-motiveforce from this electrochemical gradientcan be used to make ATP by chemiosmosis. ~ Cytochromes pass electrons |
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Methods of Producing ATP: Substrate-level phosphorylation |
~ ATP is made by transferring aphosphate group from an intermediate substrate to ADP. Note, this is a direct way to do it. ~ Glycolysis & Citric Acid Cycle |
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Methods of Producing ATP: Oxidative phosphorylation |
~ Inthe electrontransport chain (step4) a protongradientprovides energy for ATP production; the membrane protein ATP synthaseusesthis energy to phosphorylate ADP to form ATP. Notethis is an indirect way to do it. |
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Regulation of Glycolysis (and the Citric Acid Cycle) |
~ Almost all metabolic reactionsare regulated so they can be sped up, sloweddown or stopped altogether. ~ This can be done by controllingproduction or activation of enzymes forexample using feedback inhibition. |
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ATP Synthase Structure |
~ATP synthase is an enzyme complex consisting of twocomponents: -An ATPase “knob” (F1 unit) -A membrane-bound, proton-transportingbase (F0 unit) ~The units are connected by a rotor, which spins the F1 unit, and a stator, which interacts with the spinning F1 unit. ~Protons flowing through the F0 unit spin the rotor. ~As the F1 unit spins, its subunits change shape,and catalyze the phosphorylation of ADP to ATP. ~25of the 29 ATP molecules produced per glucose are produced here |
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Oxygen as a Final Electron Acceptor |
~ Most effective electronacceptor because it is highly electronegative. ~ Large difference between thepotential energy of NADH and O2electrons. ~ Cells that do not use oxygen cannotgenerate such a large potential energy difference. Thus, they make less ATPthan cells that use aerobic respiration. |
