Fatty Acid Metabolism

Question 1

Anhydrous

Answer 1

Contains no water.

Question 2

Bile Salts

Answer 2

Highly amphipathic cholesterol derivatives containing a charged acidic group.

Question 3

What do bile salts do?

Answer 3

Break down fat globules.

Question 4

How do animals store chemical energy?

Answer 4

Lipids.

Question 5

Chylomicrons

Answer 5

Packaged lipids and proteins that travel through the lymph system.

Question 6

Steps of Fatty Acid Synthesis

Answer 6

1. Joining Reaction
2. Reduction
3. Loss of Water
4. Reduction

Question 7

Steps of Fatty Acid Oxidation

Answer 7

1. Oxidation
2. Gain of Water
3. Oxidation
4. Splitting Reaction

Question 8

Where are fatty acids catabolized?

Answer 8

Mitochondria.

Question 9

What vitamin carries activated long chain fatty acids into the mitochondria?

Answer 9

Carnitine.

Question 10

Where does fatty acid beta-oxidation take place?

Answer 10

Mitochondrial Matrix.

Question 11

Four recurring reactions in fatty acid beta-oxidation.

Answer 11

1. Oxidation by FAD
2. Hydration
3. Oxidation by NAD+
4. Thiolysis by CoA

Question 12

What are the products for each cycle of beta-oxidation?

Answer 12

FADH2
NADH and H+
Acetyl CoA
Acyl-CoA (fatty acid shortened by 2 carbons)

Question 13

In the first reaction of fatty acid metabolism, acyl-CoA is oxidized by ________?

Answer 13

Acyl-CoA dehydrogenase

Question 14

In the second reaction of fatty acid metabolism, enoyl-CoA is hydrated by ________?

Answer 14

Enoyl-CoA hydratase

Question 15

In the third reaction of fatty acid metabolism, the C3 carbon is oxidized by ________?

Answer 15

L-3-hydroxyacyl CoA dehydrogenase

Question 16

What is the fourth and final step of fatty acid beta-oxidation?

Answer 16

Cleavage of ketoacyl CoA by B-betothiolase.

Question 17

Where does the Acetyl-CoA produced in B-oxidation go?

Answer 17

Citric Acid Cycle

Question 18

How much ATP does the oxidation of palmitate (16:0) yield?

Answer 18

106 ATPs

Question 19

What is the difference in the oxidation of unsaturated fatty acids?

Answer 19

Requires additional enzymes. FADH2 is not generated and 1 less ATP is yielded.

Question 20

What is the difference in the oxidation of fatty acids containing an odd number of carbons?

Answer 20

Requires additional enzymes. Results in 1 molecule of acetyl-CoA and one molecule of propionyl CoA.

Question 21

What does propionyl CoA yield and how does it compare to palmitate?

Answer 21

1 NADH, 1 FADH2, and 1 GTP. Produces 6 less ATP compared to palmitate.

Question 22

When oxaloacetate levels are low, what happens to the level of acetyl-CoA, and what is done about it?

Answer 22

Level of Acetyl-CoA increases and is converted into ketone bodies.

Question 23

What is the advantage of ketone bodies compared to fatty acids?

Answer 23

Soluable in aqueous solution unlike fatty acids.

Question 24

What is the disadvantage of ketone bodies compared to fatty acids?

Answer 24

Ketone bodies are acidic and can cause acidosis or tissue damage.

Question 25

Where does fatty acid synthesis occur?

Answer 25

Cytosol

Question 26

How much ATP is needed for the overall transfer of acetyl-CoA to the cytosol and transfer of reducing equivalents from NADH to NADPH?

Answer 26

2 ATP

Question 27

What is the regulated step in fatty acid synthesis?

Answer 27

Formation of malonyl CoA

Question 28

Why is the formation of malonyl CoA the regulated step?

Answer 28

1. Exergonic 2. Occurs early 3. Product made is dedicated to the pathway

Question 29

What is ACP and what does it do?

Answer 29

Acyl Carrier Protein. Domain of fatty acid synthase holds reaction intermediates.

Question 30

What are the four steps of elongation reactions of fatty acid synthase?

Answer 30

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

Question 31

What is the inhibited step in fatty acid synthesis?

Answer 31

Acetyl CoA carboxylase reaction.

Question 32

What is activated by high AMP levels?

Answer 32

AMPK

Question 33

What hormones inhibit fatty acid synthesis and how?

Answer 33

Epinephrine and glucagon by inhibiting PP2A phosphatase

Question 34

What hormones activate fatty acid synthesis and how?

Answer 34

Insulin by activating PP2A phosphatase

Question 35

What is the major product of fatty acid synthase?

Answer 35

Palminate

Question 36

In eukaryotes, longer fatty acids are formed from palmitate by enzymes located where?

Answer 36

Outer surface of endoplasmic reticulum

Question 37

Elongation reactions use what as an activated precursor and add one two-carbon unit at a time.

Answer 37

Malonyl CoA

Question 38

What can oleate do by a combination of chain elongation and desaturation reactions?

Answer 38

Form other unsaturated fatty acids.