Exam 2: Cholesterol

Question 1

Cholesterol functions in modulating

Answer 1

Cell membrane fluidity

Question 2

Highest concentration of cholesterol in

Answer 2

Plasma membranes

Question 3

Cholesterol is precursor.to

Answer 3

Bile salts

Steroid hormone

Question 4

Most cholesterol is ___ though the hydroxyl group to many LCFAs

Answer 4

Esterified

Question 5

Enzyme that esterifies cholesterol

Answer 5

Acyl CoA cholesterol acyl transferase (ACAT)

Question 6

Most human cells can make __

Answer 6

Cholesterol

Question 7

___ is primary site of cholesterol synthesis

Answer 7

Liver

Question 8

Other main locations that make cholesterol

Answer 8

Intestine
Adrenal cortex
Gonads

Question 9

Cholesterol synthesis occurs in the

Answer 9

Cytosol

Question 10

Some enzymes in cholesterol synthesis are bound to the

Answer 10

Endoplasmic reticulum

Question 11

Reducing power in cholesterol synthesis comes from

Answer 11

NADPH

Question 12

Energy in cholesterol synthesis comes from

Answer 12

Thioester cleavage

ATP

Question 13

Carbon atoms in cholesterol synthesis comes from 3 things

Answer 13

1. Oxidation of LCFA (OHOT)
2. Oxidation of pyruvate (glycolysis)
3. Oxidation of ketogenic AA

Question 14

HMG-CoA goes to mevalonate via

Answer 14

HMG CoA reductase

Question 15

Committed step in cholesterol synthesis

Answer 15

Mevalonate

Question 16

4 basic steps in cholesterol synthesis

Answer 16

1. Formation of mevalonate
2. Formation of activated isoprenes (5C)
3. Six isoprenes to form squalene (30C)
4. Formation of cholesterol

Question 17

Rate limiting enzyme in cholesterol synthesis

Answer 17

HMG CoA reductase

Question 18

HMG CoA reductase is embedded in the

Answer 18

SER membrane

Question 19

Regulation of HMG CoA reductase

Answer 19

1. Insulin activates
2. Glucagon deactivates
3. Controls transcription of HMG CoA reductase protein

Question 20

When HMG CoA reductase is phosphorylated by glucagon, it is

Answer 20

Deactivated

Question 21

When HMG CoA is dephosphorylated by insulin, it is

Answer 21

Activated

Question 22

Primary bile acids are make in the

Answer 22

Liver

Question 23

Primary bile acids are secreted in the

Answer 23

Duodenum

Question 24

Secondary bile acids are make in the

Answer 24

Intestine

Question 25

Secondary bile acids are are ____ enzymes that act on _____

Answer 25

Bacterial

Primary bile salts

Question 26

___ of bile salts are recovered

Answer 26

95%

Question 27

Bile salts are removed from the lumen at

Answer 27

Terminal ileum

Question 28

Bile salts are transported in blood via ____ to liver

Answer 28

Enterohepatic circulation

Question 29

___ cannot be metabolized in humans

Answer 29

Ring structure of cholesterol

Question 30

Ingredients for cholesterol

Answer 30

1. Acetyl CoA
2. NADPH
3. ATP

Question 31

First unique compound in cholesterol synthesis

Answer 31

Mevalonate

Question 32

Main enzyme in cholesterol synthesis

Answer 32

HMG CoA reductase

Question 33

All bile salts end in

Answer 33

• cholic acid

- cholate