Exam II - Fat Synthesis

Question 1

Where does fat building take place?

Answer 1

the liver

Question 2

T/F Eating fat stimulates fast synthesis.

Answer 2

False.

Question 3

T/F Eating lots of sugar stimulates fast synthesis.

Answer 3

True.

Question 4

T/F If energy charge is low when sugar enters the cell then it will run glycolysis and Kreb’s cycle?

Answer 4

True.

Question 5

Where is GLUT 2 located?

Answer 5

the liver

Question 6

Is GLUT 2 insulin independent or is it stimulated by insulin?

Answer 6

insulin independent

Question 7

Where is GLUT 4 located?

Answer 7

muscle

Question 8

Is GLUT 4 insulin independent or is it stimulated by insulin?

Answer 8

stimulated by insulin

Question 9

How does glucose enter into muscle and fat tissue?

Answer 9

facilitated diffusion

Question 10

T/F As long as the concentration of glucose is lower in muscle, glucose will move fro the blood to the muscle.

Answer 10

True.

Question 11

T/F AMP and insulin both cause translocation of GLUT 4.

Answer 11

True.

Question 12

What do muscle cells do to incoming glucose to maintain a lower concentration gradient?

Answer 12

add a phosphate to the glucose, making glucose 6 phosphate

Question 13

T/F When muscle energy is low, glucose 6 phosphate runs through glycolysis, prep step, and Kreb’s cycle to make more ATP.

Answer 13

True.

Question 14

T/F When muscle glycogen is low, glucose 6 phosphate is converted into glycogen.

Answer 14

True.

Question 15

Is exercise equal to a a high energy charge or low energy charge?

Answer 15

low energy charge

Question 16

Choose the correct response:

Glucose inhibits/facilitates hexokinase in the muscle cell, which stops diffusion.

Answer 16

inhibits

Question 17

Where is glucokinase located?

Answer 17

the liver

Question 18

Where is hexokinase located?

Answer 18

muscle cells

Question 19

List the four things that we needed to memorize about glucokinase.

Answer 19

1. Glucokinase has a lower affinity for glucose than hexokinase
2. It’s not inhibited by its product
3. It’s stimulated by insulin
4. It’s stimulated by fructose

Question 20

Choose the correct response:
If glucose does not need to go through glycolysis (high energy charge) and glycogen is full, the high energy charge will inhibit/stimulate PFK.

Answer 20

inhibit

Question 21

T/F Glucose 6 phosphate inhibits hexokinase.

Answer 21

True.

Question 22

Does liver glycolysis run faster or slower during fat building?

Answer 22

faster, because of the 4 properties of glucokinase.

Question 23

Does fat synthesis in the liver occur in the cytosol or mitochondrial matrix?

Answer 23

cytosol

Question 24

What inhibits isocitrate dehydrogenase, causing citrate to spill out of the mitochondria?

Answer 24

ATP

Question 25

T/F Isocitrate dehydrogenase in a regulatory enzyme.

Answer 25

True.

Question 26

T/F Pyruvate dehydrogenase is running during fat building.

Answer 26

True.

Question 27

What does pyruvate dehydrogenase do?

Answer 27

It converts pyruvate to acetyl CoA.

Question 28

What enzyme converts citrate to Acetyl CoA (and OAA) in the cytosol?

Answer 28

citrate lyase (membrane bound protein in the mitochondria)

Question 29

Which of the following is correct order of substrates for fat synthesis? A. Malonyl CoA -> acetyl CoA -> Palmitate B. Palmitate -> Malonyl CoA -> acetyl CoA C. Acetyl CoA -> Malonyl CoA -> Palmitate

Answer 29

C.

Question 30

What is the name of the enzyme that converts acetyl CoA to malonyl CoA?

Answer 30

acetyl CoA carboxylase

Question 31

Name the multi-enzyme complex that connects malonyl CoA units together to form palmitate.

Answer 31

fatty acid synthase (FAS)

Question 32

Does citrate stimulate or inhibit acetyl CoA carboxylase?

Answer 32

stimulate

Question 33

Does malonyl CoA stimulate or inhibit acetyl CoA carboxylase?

Answer 33

inhibit

Question 34

Does insulin stimulate or inhibit acetyl CoA carboxylase?

Answer 34

stimulate

Question 35

Does palmitoyl CoA stimulate or inhibit acetyl CoA carboxylase?

Answer 35

inhibit

Question 36

Does epinephrine stimulate or inhibit acetyl CoA carboxylase?

Answer 36

inhibit

Question 37

What are the four reactions used by FAS?

Answer 37

Condenses (adds malonyl CoA) Reduces (with NADPH) Dehydrates Reduces (with NADPH)

Question 38

What is the name of the enzyme that releases the fatty acid from FAS?

Answer 38

palmitoyl thioesterase

Question 39

Name the three enzymes that synthesize fat.

Answer 39

citrate lyase, acetyl CoA carboxylase, FA synthase

Question 40

What does citrate lyase do?

Answer 40

converts citrate to acetyl CoA

Question 41

What does acetyl CoA carboxylase do?

Answer 41

converts acetyl CoA to malonyl CoA

Question 42

What does FA synthase do?

Answer 42

links malonyl CoAs together to make palmitate via CRDR

Question 43

What is the name of the class of enzymes used to elongate palmitate?

Answer 43

elongases

Question 44

What is the name of the class of enzyme used to desaturate palmitate?

Answer 44

desaturases

Question 45

``` Humans cannot create double bonds beyond which carbon? A. 6-7th B. 7-8th C. 9-10th D. 11-12th ```

Answer 45

C.

Question 46

Where does degradation of fat occur? A. cytosol B. mitochondria

Answer 46

B.

Question 47

Low dose fructose causes which of the following in the liver? A. It reduces glycogen synthesis B. It has no effect C. It causes a twofold increase in glycogen synthesis D. It causes a threefold increase in glycogen synthesis

Answer 47

D.

Question 48

Choose the correct answer: | The liver preferentially takes in glucose/fructose.

Answer 48

fructose

Question 49

T/F Fructose is regulated by PFK.

Answer 49

False, fructose skips the regulation of PFK.

Question 50

T/F Fructose stimulates glucokinase.

Answer 50

True.

Question 51

``` Which of the following stimulate fat synthesis? A. High energy charge B. Lots of Acetyl CoA C. Lots of NADH and FADH D. Lots of Citrate E. Lots of sugar (glucose and fructose) F. Insulin ```

Answer 51

All of them stimulate fat synthesis.