Lecture 17 - Fatty Acid Oxidation and Ketone Metabolism

Question 1

Conditions promoting FA catabolism from adipose tissue include fasting, physical exertion, and stress. What two major hormones are increased by physical exercise and stress?

Answer 1

1. Epinephrine

2. ACTH

Question 2

Which is NOT a tissue that uses FA as a major fuel?

A. Liver
B. Muscle
C. Heart
D. RBCs
E. Kidney

Answer 2

D - RBCs can’t oxidize FA because they don’t have mitochondria.

Question 3

_______ in the plasma binds free 99% of FFA.

Answer 3

Albumin

Question 4

__________ binds FA that diffuse across membranes of tissues and, once bound, prevents them from diffusing out of the cell.

Answer 4

Fatty acid binding protein (FABP)

Question 5

The regulated step in fatty acid oxidation involves what enzyme?

A. CAT-I
B. VLCAD
C. MCAD

Answer 5

A - inhibiting CAT-I essentially inhibits most FA oxidation since CAT-I is used to move long-chain FAs across the IMM.

Question 6

How much ATP is generated from the total oxidation of palmitic acid to CO2 and H2O?

Answer 6

131 - 2 = 129 ATP

Question 7

_________ deficiency leads to a decrease in the ability to oxidize FA; characterized by nonketonic hypoglycemia.

A. CAT-I
B. VLCAD
C. MCAD
D. Carnitine

Answer 7

A

Question 8

_______ deficiency is the most common genetic defect in FA oxidation.

A. CAT-I
B. VLCAD
C. MCAD
D. Carnitine

Answer 8

C

Question 9

_______ deficiency would lead to the most severe consequences because without it no long-chain FA can be oxidized.

A. CAT-I
B. VLCAD
C. MCAD
D. Carnitine

Answer 9

B

Question 10

________ can form acyl-carnitines that are excreted, resulting in less carnitine available for the carnitine shuttle.

Answer 10

Low MW organic acids (such as valproic acid)

Question 11

Peroxisomes are important for the oxidation of which two types of fatty acids?

Answer 11

1. Very long chain (VLCFA; C26+)

2. Branched chain

Question 12

Where is Beta-oxidation in peroxisomes moved once the FAs are 8-10 carbons?

Answer 12

Mitochondria

Question 13

Degradation of branched-chain amino acids is initiated by an __________.

Answer 13

a-oxidation pathway

Question 14

________ is a genetic deficiency in alpha-hydroxylase, which initiates BCFA a-oxidation.

A. Zellweger Syndrome
B. Refsum’s disease
C. Gaucher’s disease
D. Tay Sach’s disease

Answer 14

B

Question 15

_________ is the absence of peroxisomes and the inability to synthesize plasmalogens.

A. Zellweger Syndrome
B. Refsum’s disease
C. Gaucher’s disease
D. Tay Sach’s disease

Answer 15

A - there is no treatment for Zellweger Syndrome.

Question 16

Acetyl-CoA carboxylase (ACC) is ALLOSTERICALLY activated by:

A. Citrate
B. Glucagon
C. Insulin
D. Malonyl-CoA

Answer 16

A

Question 17

ACC produces _______ which inhibits CAT-I.

A. Citrate
B. Glucagon
C. Insulin
D. Malonyl-CoA

Answer 17

D

Question 18

_______ is activated by glucagon via cAMP-dependent phosphorylation.

A. CAT-I
B. Acetyl-CoA carboxylase (ACC)
C. Hormone-Sensitive Lipase

Answer 18

C

Question 19

_______ is hormonally activated by insulin via dephosphorylation.

A. CAT-I
B. Acetyl-CoA carboxylase (ACC)
C. Hormone-Sensitive Lipase

Answer 19

B

Question 20

What are the two major types of ketone bodies?

Answer 20

1. Acetoacetate

2. B-hydroxybutyrate

Question 21

_________ is the enzyme that condenses 2 acetyl-CoA to get acetoacetyl-CoA (a reversible reaction).

A. HMG-CoA synthase
B. HMG-CoA lyase
C. Thiolase
D. B-hydroxybutyrate DH

Answer 21

C

Question 22

______ adds another acetyl-CoA to acetoacetyl-CoA to get hydroxymethylglutaryl-CoA.

A. HMG-CoA synthase
B. HMG-CoA lyase
C. Thiolase
D. B-hydroxybutyrate DH

Answer 22

A

Question 23

___________ catalyzes cleavage into acetoacetate and acetyl-CoA.

A. HMG-CoA synthase
B. HMG-CoA lyase
C. Thiolase
D. B-hydroxybutyrate DH

Answer 23

B

Question 24

________ uses NADh to convert acetoacetate to B-hydroxybutyrate (a reversible reaction).

A. HMG-CoA synthase
B. HMG-CoA lyase
C. Thiolase
D. B-hydroxybutyrate DH

Answer 24

D

Question 25

_________ is the most prevalent lysosomal storage disorder.

A. Zellweger Syndrome
B. Refsum’s disease
C. Gaucher’s disease
D. Tay Sach’s disease

Answer 25

C