Metabolism 2

Question 1

Glycolysis is a series of 10 anaerobic reactions that occur in the cytosol, during which glucose is split into two three-carbon pyruvate molecules. Glycolysis yields, overall, two molecules of ATP and one molecule of NADH.

Under anaerobic conditions, pyruvate is reduced to lactate and NADH is oxidized back into NAD+.

Under aerobic conditions, pyruvate moves into the mitochondria and is oxidized to yield acetyl-CoA and carbon dioxide.

Answer 1

The citric acid cycle is a series of eight aerobic reactions that take place in the mitochondrial matrix during which oxidation-reduction reactions generate NADH and FADH2.

Question 2

Oxidative phosphorylation consists of three processes:

• Electrons are transferred from NADH and FADH2 to the________
• The final electron acceptor is________ , which is ________ to become ________.
• The ________ drives the pumping of hydrogen ions into the mitochondrial intermembrane space.
• Hydrogen ions flow back into the matrix through ________ , which causes it to release its newly formed ATP.

The overall yield from all parts of glucose catabolism and ATP synthesis is about________ ATP per glucose molecule.

Answer 2

Oxidative phosphorylation consists of three processes:

• Electrons are transferred from NADH and FADH2 to the electron transport chain (ETC).
• The final electron acceptor is oxygen, which is reduced to become water.
• The electromotive force drives the pumping of hydrogen ions into the mitochondrial intermembrane space.
• Hydrogen ions flow back into the matrix through ATP synthase, which causes it to release its newly formed ATP.

The overall yield from all parts of glucose catabolism and ATP synthesis is about 38 ATP per glucose molecule.

Question 3

The final electron acceptor is ______, which is ______to become ______.

Answer 3

The final electron acceptor is oxygen, which is reduced to become water.

Question 4

The _______________ drives the pumping of hydrogen ions into the _______________.

Answer 4

The electromotive force drives the pumping of hydrogen ions into the mitochondrial intermembrane space.

Question 5

Hydrogen ions flow back into the matrix through __________, which causes it to release its newly formed ATP.

Answer 5

Hydrogen ions flow back into the matrix through ATP synthase, which causes it to release its newly formed ATP.

Question 6

The overall yield from all parts of glucose catabolism and ATP synthesis is about ______ ATP per glucose molecule.

Answer 6

The overall yield from all parts of glucose catabolism and ATP synthesis is about 38 ATP per glucose molecule.

Question 7

Triglycerides are catabolized in the following way:

Glycerol is converted into glyceraldehyde-3-phosphate and fed into glycolysis.

Fatty acids are oxidized in two-carbon units by the process β-oxidation,which yields seven each of NADH and FADH2 and a molecule of acetyl-CoA.

Under certain conditions β-oxidation can produce ketone bodies.

Answer 7

Triglycerides are catabolized in the following way:

Glycerol is converted into glyceraldehyde-3-phosphate and fed into glycolysis.

Fatty acids are oxidized in two-carbon units by the process β-oxidation,which yields seven each of NADH and FADH2 and a molecule of acetyl-CoA.

Under certain conditions β-oxidation can produce ketone bodies.

Question 8

Amino acid catabolism begins in the _____with ____________.

Answer 8

Amino acid catabolism begins in the liver with transamination.

This process yields a carbon skeleton that is fed into oxidative catabolism, and the amino acid glutamate, which is eliminated from the body via the urea cycle.