Lecture 14 - Fatty Acid Biosynthesis

Question 1

What is fatty acid biosynthesis?

Answer 1

the liver and adipose tissue can synthesize fatty acids from acetyl-CoA

Question 2

Acetyl-CoA can be from ___ or ____

Answer 2

carbohydrates or amino acids

Question 3

Acetyl-CoA is formed where? Thus, where does it have to be transported?

Answer 3

Acetyl-CoA is formed in the mitochondria and has to be exported to the cytosol

Question 4

What are the 3 stages of fatty acid biosynthesis?

Answer 4

1. Export of acetyl-coA into the cytosol
2. Carboxylation of acetyl-coA to malonyl-coA
3. Sequential addition of 2-carbon fragments to form palmitate

Question 5

Acetyl-CoA produced in the mitochondria is carried away by what molecule into the cytosol?

Answer 5

citrate

Question 6

Acetyl-CoA is condensed with ______ in the citrate ____ reaction

Answer 6

OXALOACETATE in the citrate synthase reaction

Question 7

The export of acetyl-CoA into the cytosol is a _____ way of using the citrate shuttle

Answer 7

indirect

Question 8

The carboxylation of acetyl-CoA to malonyl-CoA is catalyzed by what enzyme?

Answer 8

acetyl-CoA carboxylase

Question 9

what step of fatty acid biosynthesis is the principle regulatory site?

Answer 9

the carboxylation of acetyl-CoA to malonyl-CoA

Question 10

The carboxylation of acetyl-CoA to malonyl-CoA is controlled by _____ regulation and ____ modification

Answer 10

allosteric regulation and covalent modification

Question 11

What is the POSITIVE regulator of Acetyl-CoA carboxylase?

Answer 11

citrate

Question 12

What is the NEGATIVE regulator of Acetyl-CoA carboxylase?

Answer 12

Fatty Acyl-CoA

Question 13

the carboxylation of acetyl-coA to malonyl-CoA requires….

Answer 13

ATP

Question 14

what enzyme catalyzes the last step of fatty acid biosynthesis?
(Sequential addition of two-carbon fragments to form palmitate)

Answer 14

Palmitate Synthase

Question 15

What are the 5 general reactions in the 3rd step of fatty acid biosynthesis

Answer 15

1. Loading
2. Condensation
3. Reduction
4. Dehydration
5. Reduction

Question 16

What is the name for elongation enzymes?

Answer 16

elongases

Question 17

What do elongase enzymes do?

Answer 17

increase the number of carbons

Question 18

What is the name for desaturation enzymes?

Answer 18

Desaturases

Question 19

What do desaturase enzymes do?

Answer 19

form double bonds

Question 20

Both elongase and desaturase enzymes are located where?

Answer 20

in the endoplasmic reticulum

Question 21

Fatty acid biosynthesis uses what 3 things to form fatty acids?

Answer 21

ATP, NADPH, acetyl-coA

Question 22

Acetyl-CoA is used as a _____ in fatty acid biosynthesis

Answer 22

building block

Question 23

NADPH is used as a ____ in fatty acid biosynthesis

Answer 23

reducing power

Question 24

Why is ATP needed in fatty acid biosynthesis?

Answer 24

building up always requires energy

Question 25

What part of acetyl-CoA is used as a building block in fatty acid biosynthesis?

Answer 25

the acetyl group (2carbon unit) is oxidized