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33 Cards in this Set
- Front
- Back
- 3rd side (hint)
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Redox Reactions |
transfer of electrons
1) oxidation: loss of electrons -oxidizing agent accepts electrons -if hydrogens were lost, oxidized 2) reduction: gain of electrons (adding electrons) reducing agent donates electrons if hydrogens were gained, reduction |
2 types
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Compare aerobic glucose metabolism with combustion of methane
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1) both are exergonic
2) glucose metabolism has many steps and produces energy that can be harvested, combustion does not |
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Complete oxidation of glucose
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C6H12O6 + 6O2 -> 6CO2 + 6H2O + Energy (ATP + Heat) Glucose + oxygen -> carbon dioxide + water + energy (ATP + heat)
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Substrate-level phosphorylation
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1) substrate-level phosphorylation: making ATP by transferring a phosphate from an organic substrate to ADP
- powered by the phosphate transfer (?) -reactants: substrate and ADP - stages 7 and 10 of glycolysis - produces less ATP than oxidative |
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In which stages of cellular respiration is ATP produced by substrate-level phosphorylation?
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Glycolysis: 2 ATP
Citric acid cycle: 2 ATP |
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Oxidative phosphorylation
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2) oxidative phosphorylation: making ATP from ADP and Pi (inorganic phosphate)....etc + chemiosmosis
-powered by redox reactions of an electron transfer chain -reactants: NADH, FADH2 (oxidized) |
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How many ATP produced by oxidative phosphorylation (etc and chemiosmosis)?
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26 or 28 ATP
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Where do Glycolysis, pyruvate oxidation, and the citric acid cycle occur?
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1) Glycolysis: cytosol
2) Pyruvate oxidation: mitochondria 3) Citric acid cycle: mitochondria |
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What are the initial reactants (1) and end products (2) for glycolysis? What is oxidized (3) and what is reduced (4) ?
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Glycolysis:
1) glucose 2) 2 ATP, 2 pyruvate, 2 NADH 3) sugar 4) NAD |
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Coenzymes
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small molecules required by some enzymes
- bind to enzymes and chemically alter them - molecular "handles" NAD: reduction: hydrogen is added at top of hexose to make NADH oxidation: a hydrogen is taken off of the top of NADH |
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How many steps do the catabolic pathways of glycolysis (1), pyruvate oxidation (2), and the citric acid cycle (3) each have?
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1) 10 steps
2) 3 steps 3) 8 steps (cycle = regeneration) |
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Energy investing and energy harvesting (payoff)
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energy investing stage: steps 1 through 5
- 2 ATP are used - steps 1 and 3 energy harvesting (payoff) stage: steps 6 through 10 - 4 ATP are formed - 2 in step 7 and 2 in step 10 |
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How many CO2 are produced from complete oxidation of glucose?
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- 1 in pyruvate oxidation
- 2 in citric acid cycle |
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Structure of an acetyl group
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C=O
| CH3 |
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What has happened by the end of the citric acid cycle and what are the total products?
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Glucose catabolism is complete
- 4 ATP, 10 NADH, 2 FADH2 |
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When did Krebs discover the cycle? When did he win the Nobel Prize?
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- discovered around 1937
- won prize in 1953 - knighted in 1958 |
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How many cycles are required to complete catabolism of 1 glucose?
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Two cycles. Everything doubles after step 6 of glycolysis.
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What is the electron transport chain and where is it found?
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A chain of proteins within the inner membrane of mitochondria
- 4 complexes of proteins - several cytochrome proteins. - performs a series of redox reactions 1) chain protiens transfer protons cross inner membr |
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How does the potential energy of an electron change as it moves down the chain?
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It decreases to an energy minimum
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How do the electronegativities of the chain molecules differ along the chain?
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They alternate between oxidized (less electronegative) and reduced (more electronegative) states.
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Chemiosmosis
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The use of a proton gradient to make ATP
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1) In which stages of cellular respiration is ATP made?
2) In which is it consumed? 3) In which are coenzymes reduced? 4) In which are they oxidized? |
1) Glycolysis: 4 total, 2 net. Citric acid cycle: 2 (per glucose)
2) Glycolysis: 2 3) Glycolysis: NAD. Pyruvate oxidation: NAD. Citric acid cycle: NAD and FAD 4) Electron transport chain: NADH |
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What is the path of energy flow through cellular respiration? (there are 4 transfers)
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glucose -> NADH -> etc -> proton gradient -> ATP
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What do each of the 4 stages of cellular respiration do?
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1) stages 1 through 3 oxidize glucose
-transfer H to NAD making NADH (reduces NAD) - make ATP (by S.L.P???) 2) stage 4 oxidizes NADH -ATP synthase makes ATP by energy of proton gradient |
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What is the final tabulation of ATP per glucose after cellular respiration? What about CO2 and H2O?
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Glycolysis: 2 ATP, 4 H2O
Pyruvate oxidation: 2 CO2 Citric acid cycle: 2 ATP, 4 CO2 Oxidative phosphorylation: 32 ATP, 2 H2O Total ATP: 36 |
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Which reactant of glycolysis must be recycled to keep it running? What are the differences between alcohol and lactic acid fermentation?
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- NADH is oxidized by pyruvate or a derivative of such to regenerate NAD
fermentation: - the NAD oxidizes sugar by glycolysis - 2 net ATP by substrate-level phosphorylation 1) alcohol fermentation: 2 ethanol as end product 2) lactic acid fermentation: 2 lactate as end product |
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At which of the first 3 stages of cellular respiration does each fuel enter?
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1) Proteins (amino acids):
- pyruvate of glycolysis - acetyl coA of pyruvate oxidation - citric acid cycle 2) Carbs (sugars): - glycolysis 3) Fats - glycerol -> G3P of glycolysis - fatty acids -> acetyl coA |
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What are carb, lipid, and protein functions? (there are 2)
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1) storage
2) carbon source |
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What do catabolic pathways provide to anabolic ones that enable them to build?
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Intermediates are used for anabolic pathways
1) glycolysis -> pyruvate 2) acetyl coA -> citric acid cycle |
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In which step of what pathway does phosphofructokinase (PFK) catalyze?
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3rd step of glycolysis
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How does PFK regulate cellular respiration? (Include all metabolites incolved and their role in feedback inhibition)
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1) has allosteric sites (can be positively or negatively regulated)
- AMP stimulates - ATP and Citrate inhibit 2) controlled by feedback inhibition |
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What are the initial reactants (1) and end products (2) for the citric acid cycle? What is oxidized (3) and what is reduced (4)?
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Citric acid cycle:
1) Acetyl coA 2) 1 ATP, 3 NADH, 1 FADH2, 2 CO2 (double per glucose) 3) Isocitrate, 2 other substrates 4) NAD |
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What are the initial reactants (1) and end products (2) for pyruvate oxidation? What is oxidized (3) and what is reduced (4)?
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Glycolysis:
1) glucose 2) 2 ATP, 2 pyruvate, 2NADH 3) G3P (?) 4) NAD |
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