13A: Fatty Acid and Triglyceride Synthesis

Question 1

Lipogenesis

Answer 1

synthesis of fatty acids

Question 2

Where does lipogenesis occur?

Answer 2

adipose tissue, liver, mammary glands

Question 3

What is the main function of GLUT4 in lipogenesis?

Answer 3

delivers glucose to adipose tissue to make into fatty acids

Question 4

What is the main function of acetyl CoA carboxylase in lipogenesis?

Answer 4

enzyme that catalyzes the initial step to convert acetyl CoA to malonyl CoA

Question 5

What is the main function of lipoprotein lipase in lipogenesis?

Answer 5

delivers fatty acids from circulating lipoproteins to tissues for use or storage

Question 6

What is the main function of fatty acid synthase in lipogenesis?

Answer 6

adds 2 C units to a growing FA chain

Question 7

What does acetyl CoA carboxylase require?

Answer 7

biotin and ATP

Question 8

What is the main substrate for FA synthesis?

Answer 8

malonyl CoA

Question 9

What molecule is needed a lot of for FA synthesis?

Answer 9

NADPH

Question 10

FA synthesis summary

Answer 10

acetyl CoA (2C) and malonyl CoA (3C) release a CO2 and combine to form a 4C molecule

Question 11

Where does FA chain elongation occur?

Answer 11

mitochondria

Question 12

What molecules are used in FA chain elongation?

Answer 12

acetyl CoA and NADH

Question 13

Acetyl CoA sources for FA synthesis

Answer 13

1. blood glucose after a meal is taken up by adipose tissue and liver
2. amino acid catabolism

Question 14

How is blood glucose taken up by adipose tissue?

Answer 14

1. insulin stimulates GLUT 4 translocation
2. glucokinase phosphorylates glucose in liver
3. glycolysis occurs to produce acetyl CoA
4. insulin dephosphorylates and activates acetyl CoA carboxylase

Question 15

How is acetyl CoA transported from the mitochondria to the cytosol?

Answer 15

transported in the form of citrate

Question 16

Where is NADPH acquired for FA synthesis?

Answer 16

1. pentose phosphate pathway
2. malic enzyme

Question 17

How does malic enzyme generate NADPH?

Answer 17

1. acetyl CoA and OAA produce citrate in mitochondria
2. citrate leaves mitochondria on a transporter for cytoplasm and is broken into OAA
3. acetyl CoA is converted to malonyl CoA
4. OAA is converted to malate and malic enzyme and generates NADPH, pyruvate, and CO2

Question 18

T/F: Double bonds cannot be added after C9 in mammals

Answer 18

T

Question 19

What enzymes synthesize triglyclerides?

Answer 19

acryltransferases

Question 20

Bovine DGAT1 mutation

Answer 20

alters milk fat composition and fatty acid ratios