Review 4: Lipid Metabolism

Question 1

In the fed state, what are the two products of Acetyl-CoA?

Answer 1

1) Cholesterol

2) Fatty Acyl-CoA

Question 2

What are the rate limiting enzymes in lipid metabolism?

Answer 2

1) Carnitine palmitoyltransferase (CPT)

2) Acetyl-CoA carboxylase

Question 3

What does acetyl-CoA turn into during the fasting state?

Answer 3

Ketone bodies

Question 4

What hormone initiates the acetyl coA response during fasting?

Answer 4

epinephrine

Question 5

What does epinephrine do in terms of fatty acid metabolism during the fasting state?

Answer 5

converts fatty acyl-CoAs into acetyl CoA via CPT/CAT

Question 6

What does insulin do in terms of fatty acid metabolism during the fed state?

Answer 6

converts acetyl-CoA into fatty acyl-CoA via acetyl CoA carboxylase

Question 7

What is the rate limiting enzyme in fatty acid biosynthesis?

Answer 7

acetyl CoA carboxylase

Question 8

What reaction does Acetyl CoA carboxylase catalyze?

Answer 8

acetyl CoA ————> malonyl CoA

Question 9

What is the cofactor for Acetyle CoA carboxylase?

Answer 9

Biotin

also a cofactor for Pyruvate carboxylase—carries activated CO2

Question 10

What 5 things regulate Acetyl CoA carboxylase activity?

Answer 10

ACTIVATORS:

1) Citrate
2) Insulin

INHIBITORS:

3) Palmitoyl CoA
4) Glucagon
5) Epinephrine

Question 11

In the fed state, how are FAs transported in the blood?

Answer 11

as part of TAGS on lipoproteins

Question 12

In the fasted state, how are FAs transported in the blood?

Answer 12

bound to albumin

Question 13

What carries acetyl groups from the mitochondria to the cytoplasm?

Answer 13

citrate

Question 14

What is the ONLY physiological inhibitor of rate-limiting enzyme in FAO?

Answer 14

malonyl coA (key regulator in FAO and ketone body formation)