Lesson 6: Catabolic Pathways for Lipids

Question 1

Chylomicrons are lipoproteins that are responsible for transporting exogenous (dietary) lipids. True or False?

Answer 1

True

Question 2

Excess ketone bodies are secreted in the urine. True or False?

Answer 2

True

Question 3

Fatty acids (in the form of acyl CoA) are transported from the cytoplasm to the mitochondria by

Select one:

a. Carnitine
b. Coenzyme A
c. Methionine
d. Lysine
e. Creatinine

Answer 3

a. Carnitine

Question 4

Glycerol

Select one:

a. Directly enters the electron transport chain
b. Is converted to acetyl CoA to enter the glycolysis pathway
c. Is broken down by the urea cycle
d. Is broken down by β-oxidation
e. Is converted to dihydroxyacetone phosphate to enter the glycolysis pathway

Answer 4

e. Is converted to dihydroxyacetone phosphate to enter the glycolysis pathway

Question 5

Ketone body formation occurs

Select one:

a. With very low carbohydrate diets
b. All of these answers are correct
c. When there is insufficient insulin for glucose to be effectively utilised
d. During starvation
e. When there is insufficient carbohydrates to meet the body’s energy needs

Answer 5

b. All of these answers are correct

Question 6

Lingual lipase and gastric lipase act preferentially on triglycerides containing long-chain fatty acids. True or False?

Answer 6

False

Question 7

Once the fatty acid (in the form of acyl CoA) is in the mitochondrion, β-oxidation begins. The order of steps that occur is

Select one:

a. Hydration, thiolytic cleavage, hydration, thiolytic cleavage
b. Hydration, hydration, dehydrogenation, thiolytic cleavage
c. Thiolytic cleavage, dehydrogenation, hydration, dehydrogenation
d. Dehydrogenation, thiolytic cleavage, hydration, dehydrogenation
e. Dehydrogenation, hydration, dehydrogenation, thiolytic cleavage

Answer 7

e. Dehydrogenation, hydration, dehydrogenation, thiolytic cleavage

Question 8

Propionyl CoA

Select one:

a. All of these answers are correct
b. Remains after the β-oxidation of a fatty acid with an odd number of carbons
c. Can be converted to succinyl CoA
d. Is a three carbon molecule
e. None of these answers are correct

Answer 8

a. All of these answers are correct

Question 9

The body preferentially uses fatty acids as an energy supply. True or False?

Answer 9

False

Question 10

The complete β-oxidation of stearic acid (18 carbons) yields

Select one:

a. 18 FADH2, 18 NADH and 18 acetyl CoA
b. 8 FADH2, 8 NADH and 9 acetyl CoA
c. 6 FADH2, 6 NADH and 7 acetyl CoA
d. 10 FADH2, 8 NADH and 8 acetyl CoA
e. 2 FADH2, 3 NADH and 12 acetyl CoA

Answer 10

b. 8 FADH2, 8 NADH and 9 acetyl CoA

Question 11

Triglycerides account for nearly 95% of dietary fat. True or False?

Answer 11

True

Question 12

When the fatty acid enters the cell of the metabolising tissue, it is activated by coenzyme A. This requires the equivalent of

Select one:

a. 2 ATP
b. 12 ATP
c. 6 ATP
d. 1 ATP
e. 4 ATP

Answer 12

a. 2 ATP

Question 13

Which of the following are ketone bodies?

Select one:

a. Glycerol 1-phosphate and dihydroxyacetone phosphate
b. Carnitine and Acetoacetate
c. Thiolase and enoyl CoA hydratase
d. Dihydroxyacetone phosphate and glycerol
e. Acetoacetate and β-hydroxybutyrate

Answer 13

e. Acetoacetate and β-hydroxybutyrate

Question 14

Which of the following is required for the β-oxidation of polyunsaturated fatty acids but not saturated fatty acids?

Select one:

a. Enoyl CoA isomerase
b. Enoyl CoA hydratase
c. 3-hydroxyacyl CoA dehydrogenase
d. Acyl CoA dehydrogenase
e. Thiolase

Answer 14

a. Enoyl CoA isomerase

Question 15

β-oxidation breaks down

Select one:

a. All of these answers are correct
b. Fatty acids with an even number of carbons
c. Unsaturated fatty acids
d. Saturated fatty acids
e. Fatty acids with an odd number of carbons

Answer 15

a. All of these answers are correct