Cellular Respiration

ETC
1. in cristae
  1. inner membrane of mitochondria
2. generates no ATP
  1. ATP generated by ATP synthase
3. generates a proton concentration gradient
  1. chemiosmosis
    1. the use of energy in a proton (H+) gradient to drive cellular work
  2. oxygen is the final proton acceptor
    1. ETC would not function w/o oxygen
      1. no oxidation
      2. no final proton acceptor
4. carriers alternate reduced and oxidized states as they accept and donate electrons
  1. electrons drop in free energy as they go down the chain
    1. energy being used by proton pumps
5. energy stored in H+ gradient across a membrane couples the redox reactions of the ETC to ATP synthase
Citric Acid Cycle
1. completes the energy-yielding oxidation of organic molecules
2. completes the breakdown of oxygen
3. 7 steps to decompose citrate back to oxaloacetate
4. aerobic
5. Acetyl CoA + NAD+ + FAD +2ADP + 2Pi ---> 4CO2 + 6NADH + 6H+ +2FADH2 +2ATP
  1. NADH and FADH2 account for most of the energy from food
    1. produces 3 NADH per cycle
    2. produces 2 FADH per cycle
6. takes place in mitochondrial matrix
7. oxidation of organic molecules
8. why is the citric acid cycle a cycle?
  1. the four-carbon acid that accepts the Acetyl CoA in the first step is regenerated
glycolysis
1. glucose + NAD --> 2ATP +2NADH +2 pyruvate
2. anaerobic
3. glucose gets oxidized
4. 2 phases
  1. energy investment phase
    1. energy as ATP put in
      1. 2 ATP put in
  2. energy payoff phase
    1. net creation of ATP and NADH
      1. 4 ATP ( net total of 2 ATP)
5. in cytosol
ATP Synthase
1. uses the exergonic flow of H+ to drive phosphorylation
2. creates the bulk of ATP
3. enzyme that catalyzes the formation of ATP
  1. uses ADP and an inorganic phosphate
4. oxidative phosphorylation
  1. after protons are pumped into the mitochondrial intermembrane space, they flow back to ATP synthase
    1. produces the largest number of ATP during cellular respiration
Stepwise energy harvest
1. series of steps during cellular respiration
  1. this is so energy can be stored in carrier molecules instead of being released as heat
2. allows the energy of oxidation to be released in small pockets
aerobic vs anaerobic
1. aerobic
  1. requires oxygen, produces more ATP
2. anaerobic
  1. fermentation
    1. allows cells to generate NAD for glycolysis
      1. allows continuous generation of ATP by the substrate-level phosphorylation of glycolysis
  2. produces lactic acid/ethanol
  3. does not require oxygen
ATP
1. Adenosine Triphosphate
2. necessary for energetically unfavorable reactions
3. production releases 11-13 kcal
4. excess energy converted to heat
catabolic pathway
1. exergonic
  1. "accompanied by the release of energy
Redox Reactions
1. OX: loses an electron
2. RED: gains an electron
3. the transfer of electrons releases energy
enzymes lower activation energy ands allow sugar to be oxidized
feedback inhibition
1. metabolic control
2. regulates the activity of enzymes in the glycolytic pathway
substrate level phosphorylation
1. uses inorganic phosphate to phosphorylate ADP
  1. converts ADP to ATP
  2. the addition of a phosphate to an organic compound
phosphofructokinase
1. fructose-1,6-biphosphate active site
2. rate limiting for glycolyis
3. allosteric regulatory enzyme
4. inhibitors: ATP, citrate
  1. when ATP binds, the reaction slows
5. activator: AMP
Oxidation of pyruvate
1. converting pyruvate to Acetyl CoA
2. must happen before the citric acid cycle
  1. joins citric acid cycle by combining w/ oxloacetate
3. carried out by a multi-enzyme complex
  1. intermediates are passed directly from one enzyme to another
4. oxidized and decarboxylated
  1. removed electrons used to reduce NAD+ to NADH
Biosynthesis
1. anabolic
2. uses small molecules to build other substances
  1. may come from food, glycolysis, or citric acid cycle
NAD+ is an electron acceptor
1. gets reduced to NADH

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	Criado por emma vilmenay aproximadamente 3 anos atrás