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22 Cards in this Set
- Front
- Back
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What is Step 1 in fuel oxidation
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Generation of acetyl-CoA
Carbohydrate → (NADH) Pyruvate + CoA → (NADH + CO2) acetyl-CoA |
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What is Step 2 in fuel oxidation?
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Oxidation of acetyl-CoA
Krebbs Cycle: acetyl-CoA + oxaloacetate → citrate → (++NADH and ++CO2) → oxaloacetate |
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What is Step 3 in fuel oxidation?
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Electron transfer and oxidative phosphorylation (mitochondria)
e + ADP + Pi → ATP 2H+ + 1/2O2 → H2O |
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What is the formation of NADH from carbohydrates/FA called?
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fuel oxidation
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What is the formation of a proton gradient from NADH called?
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electron transport
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What is the formation of ATP from proton gradient called?
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oxidative phosphorylation
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Does aerobic oxidation of pyruvate (from beta oxidation) produce acetyl-CoA?
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Yes- therefore greater energy production
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Does anaerobic oxidation of pyruvate produce acetyl-CoA?
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No- only produces lactic acid therefore does not produce as much ATP. However it regenerates NAD very quickly.
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What is the main rate limiting step for glycolysis: hexokinase, phosphofructokinase or pyruvate kinase?
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Phosphofructokinase- regulated by AMP levels
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What is glycogen?
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A carbohydrate store found in the liver made of chains of glucose molecules
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Can acetyl-CoA (from pyruvate) be converted back to glucose?
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No.
when pyruvate has been converted to acetyl-CoA by pyruvate dehydrogenase it cannot be made back into a carbohydrate- IRREVERSIBLE REACTION |
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Can lactic acid (from pyruvate) be converted back to glucose?
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Yes.
Pyruvate is converted to lactic acid by lactate dehydrogenase. It is then exported to the liver where it is converted back to glucose. |
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What fuel is burnt first in light exercise?
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Glucose (inhibited when blood glucose decreases too much)
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What fuel is burnt second in light exercise?
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Fatty acids, the preferred fuel during light exercise so as to conserve glucose levels. Any glucose that does enter the cell at this point is oxidised to lactate which undergoes gluconeogenesis
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When is pyruvate dehydrogenase active?
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When dephosphorylated
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What activates PDH?
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PDH phosphatase, activated by insulin.
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What deactivates PDH?
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PDH kinase, activated by high concentrations of acetyl-CoA
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When is glycogen synthase active?
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when dephosphorylated
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What activates glycogen synthase?
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Protein phosphatase 1, stimulated by insulin
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What deactivates glycogen synthase?
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glycogen synthase kinase
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What reaction does ATP-citrate lyase catalyse?
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LIPOGENESIS: splits citrate (coming from the Krebs cycle) in the cytoplasm to form acetyl-CoA (to be made into fat) and oxaloacetate
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Does white adipose tissue contain glycogen synthase?
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No-unable to synthesise glycogen. Excess glucose will be converted to fat.
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