Intro to Metabolism

Question 1

Describe the stages of catabolism:

Answer 1

Stage 1: hydrolysis of complex molecules to their component building blocks
Stage 2: conversion to acetyl coA (or other simple intermediates)
Stage 3: oxidation of acetyl coA; oxidative phosphorylation

Question 2

Energy sources in the body:

Answer 2

• ATP–high energy phosphate group
• NADH–high energy electrons
• NADPH–high energy electrons

Question 3

What is the change in free energy for the hydrolysis of ATP to ADP+Pi?

Answer 3

-8 kCal/mol

Question 4

What is deltaG?

Answer 4

the energy available to do work

Question 5

Describe the electron transport chain (ETC):

Answer 5

• final common pathway for coenzymes NADH and FADH2 produced in catabolism and the TCA cycle
• reduced coenzymes donate a pair of electrons to electron carriers
• electrons passed down ETC losing energy and generating ATP
• energy not converted to ATP is used to transport Ca2+ and generate heat

Question 6

Other than going into the TCA cycle, what other uses does acetyl coA have?

Answer 6

also a substrate for biosynthetic reactions such as synthesis of FAs, cholesterol and ketone bodies

Question 7

Is the TCA cycle catabolic or anabolic?

Answer 7

it is amphibolic (involved in anabolic and catabolic pathways)

Question 8

What does the availability of oxaloacetate regulate?

Answer 8

regulates citrate synthase activity

Question 9

What are the metabolic consequences of hypoxia/anoxia?

Answer 9

failure of oxidative phosphorylation

Question 10

What is the metabolic consequence of ischemia?

Answer 10

no ATP synthesis, shutdown of energy dependent processes, osmotic imbalance due to failure of ATP-dependent ion pumps, pyruvate dehydrogenase inhibited, increased lactate, decreased pH

Question 11

Consequences of impaired enzyme action

Answer 11

• accumulation of substrate
• deficiency of product
• diversion to alternate product