Fates of pyruvate Flashcards

1
Q

What co-factor is necessary for glycolysis?

A

NAD+ for G3P to 1,3BPG

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2
Q

What fate of pyruvate produces NAD+?

A

Pyruvate to lactate

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3
Q

What is the enzyme used for the conversion of pyruvate to lactate?

A

Lactate dehydrogenase

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4
Q

Does the muscle prefer aerobic or anaerobic conditions?

A

Aerobic. LDH-5 (M4) has a high Km (low affinity) for pyruvate but as pyruvate levels increase during exercise, the Km is reached and lactate formation begins

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5
Q

How is ethanol formed?

A

By microbes. Pyruvatepyruvate decarboxylase to Acetaldehydealcohol dehydrogenase to Ehtanol

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6
Q

What bonds are microbes breaking during fermentation?

A

B1,4 glycosidic bonds

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7
Q

What cell processes ethanol?

A

Hepatocytes (liver). The rate limiting enzyme is alcohol dehydrogenase (Km 5mg/dl)

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8
Q

Why is it impossible to run while drunk?

A

The liver uses all the NAD+ to process the alcohol, none left for glycolysis = no ATP

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9
Q

What system engages when ADH is overloaded?

A

Microsomal enzyme oxidizing system

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10
Q

Why do drugs and alcohol not mix?

A

The MEOS is responsible for clearing drugs from the system. Together, all systems are overloading resulting in longer clearing time

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11
Q

Ethanol metabolism produces high levels of NADH. What is the result of this?

A

Shifts metabolism towards fatty acid synthesis

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12
Q

What causes the alcohol beer belly?

A

Alcohol intake reduces the amount of fat that your body burns as energy

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13
Q

What is the metabolism of Ethylene glycol? (Antifreeze)

A

Elthylene glycol alcohol dehydrogenase -> Glycoahldehyde -> Oxylate, Glycolate and Glyoxylate -> stops oxidative phosphorylation and TCA cycle

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14
Q

What is the remedy to ethylene glycol poisoning?

A

Introduce alcohol to try to stimulate alcohol metabolism

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15
Q

What organ does the TCA cycle take place?

A

Liver

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16
Q

What organelle does TCA take place?

A

Mitochondria

17
Q

What is the rate limiting step of TCA?

A

Acetyl CoA to Citrate (Citrate synthase)

18
Q

How does TCA inhibit glycolysis?

A

Citrate diffuses in to cytoplasm and inhibits PFK1

19
Q

1st oxidation step of TCA?

A

Isocitrate -> a-KG, release NADH and CO2

20
Q

What steps produce NADH?

A

Isocitrate -> a-KG, a-KG to succinyl Coa, malate to ooa

21
Q

What steps produce CO2?

A

citrate -> isocitrate, isocitrate -> a-KG, a-KG -> succinyl CoA

22
Q

What steps does Arsenic inhibit?

A

Pyruvate dehydrogenase (pyruvate -> AcCoA), a-KG dehydrogenase (a-KG to SuccCoA)

Stops respiration

23
Q

What step produces a FADH2?

A

Succinate to FUmarate

24
Q

What is the coupled reaction in the TCA?

A

Malate to Oxaloacetate. Malate product is favored but since OOA and NADH are constantly removed, drives system towards making OOA

25
Q

What are TCA leaks?

A

Citrate (FA), OAA (Glucose) for other pathways

26
Q

What is the committed step for TCA?

A

Isocitrate to a-KG

27
Q

What must be reoxidized to continue cycle?

A

FAD (fumarate to malate)