Cholesterol

Question 1

All of the carbon atoms of cholesterol are derived from which molecule?

Answer 1

acetate/isoprene units

Question 2

What is cholesterol a precursor for?

Answer 2

Bile Acids, Steroids, and Vitamin D

Question 3

Where are fatty acids synthesized?

Answer 3

Mitochondria

Question 4

Where is cholesterol synthesized?

Answer 4

Cytosol

Question 5

Which 3 steps are used in Fatty Acid Oxidation that are also used in Cholesterol synthase?

Answer 5

1) 2 Acetyl CoA
- Thiolase cleaves CoA

2) Acetoaceyl CoA
- HMG CoA Synthase brings in acetyl CoA and cleaves CoA

3) 3-Hydroxy-3-methylglutaryl CoA (HMG CoA)

Question 6

Which enzyme reacts with HMG CoA to start cholesterol synthesis?

Answer 6

HMG CoA reductase

Question 7

Are we trying to make energy or store it during cholesterol synthesis?

Answer 7

make

Question 8

What is the first rate limiting step in cholesterol synthesis?

Answer 8

HMG-CoA to Mevalonate

Question 9

Which enzyme is used in the rate limiting step of cholesterol synthesis?

Answer 9

HMG-CoA reductase

Question 10

Which enzyme is used during cholesterol synthesis that acts like a kinase by transfering a high energy phosphate onto a molecule?

Answer 10

mevalonate-5-phosphotransferase

Question 11

What is formed when a phosphate is added to mevalonate?

Answer 11

Phosphomevalonate

Question 12

How many carbons make up cholesterol?

Answer 12

30 carbons long

Question 13

What is formed when a phosphate is added to phosphomevalonate?

Answer 13

5-pyrophosphomevalonate

Question 14

Which enzyme adds a phosphate onto phosphomevalonate to form 5-pyrophosphomevalonate?

Answer 14

pyrophosphomevalonate kinase

Question 15

Which enzyme is used to remove a carbon off of 5-pyrophosphomevalonate?

Answer 15

pyrophosphatemevalonate decarboxylase

Question 16

How many carbons are on an isoprene unit?

Answer 16

activated 5 carbon structure

Question 17

What is the building block of cholesterol?

Answer 17

isoprene units

Question 18

IPP and DPP are how many carbons long?

Answer 18

5 carbons long

Question 19

how many isoprene units are needed to build cholesterol?

Answer 19

6x

Question 20

What us the isomer of isopentyl pyrophosphate?

Answer 20

dimethylallyl pyrophosphate

Question 21

What molecule is formed by DPP and IPP?

Answer 21

Geranyl Pyrophosphate

Question 22

Which enzyme is used to combine DPP and IPP to form Geranyl Pyrophosphate?

Answer 22

Phenyl Transferase

Question 23

How many carbons is Geranyl Pyrophosphate consist of?

Answer 23

10 carbons

Question 24

What is formed from the condensing of GPP and an additional IPP?

Answer 24

Farnesyl Pyrophosphate?

Question 25

How many carbons is FPP consist of?

Answer 25

15

Question 26

Which enzyme adds an additional IPP onto Geranyl Pyrophosphate?

Answer 26

Phyenyl transferase

Question 27

Which enzyme adds two farnesyl pyrophosphates together?

Answer 27

squalene synthase

Question 28

How many carbons long is squalene?

Answer 28

30 carbons long

Question 29

What is the name of the molecule that makes the final form of 30 carbon chain that forms cholesterol?

Answer 29

squalene

Question 30

is squalene stable or unstable?

Answer 30

unstable because of the multiple double bonds and the fact it is so long

Question 31

How many times do the first 3 steps occur during cholesterol synthesis?

Answer 31

2x to make 2-15 carbon chains

Question 32

What is the stable ring version of squalene?

Answer 32

lanosterol

Question 33

What is lanosterol converted into by a sequence of reactions that use NADPH?

Answer 33

Cholesterol

Question 34

How many NADPH are used to stabilize lanosterol to cholesterol?

Answer 34

20x

Question 35

Is increased production of cholesterol a negative or positive feedback for HMG-CoA?

Answer 35

negative, inhibits further production of cholesterol

Question 36

Insulin _____ HMG reductase

Answer 36

increases

Question 37

Glucagon _____ HMG reductase

Answer 37

decreases

Question 38

How does cholesterol make hormones/ what does it convert to?

Answer 38

Pregnalone

Question 39

What does progesterone convert to which hormones?

Answer 39

Hydroxyprogesterone OR Corticosterone

Question 40

Corticosterone can further convert to which hormone?

Answer 40

Aldosterone

Question 41

Hydroxyprogesterone can further convert into what hormone?

Answer 41

DHEA

Question 42

DHEA can further convert into which hormone?

Answer 42

Androstenedione

Question 43

Androstenedione can further convert into what hormones?

Answer 43

Testosterone and esterone

Question 44

Testosterone can further convert into what hormones?

Answer 44

Dihydrosterone OR Esradiol

Question 45

Which hormone does estrogen come from?

Answer 45

Estradiol

Question 46

Which vitamin is derived from cholesterol?

Answer 46

Vitamin D

Question 47

Which organ produces estrogen and progesterone?

Answer 47

ovaries

Question 48

Which organ produces aldosterone and cortisol?

Answer 48

adrenal cortex

Question 49

which two hormones does the adrenal cortex produce?

Answer 49

aldosterone and cortisol

Question 50

which two hormones do the ovaries produce?

Answer 50

estrogen and progesterone

Question 51

What hormone do the testes make?

Answer 51

testosterone

Question 52

Which organ produces testosterone?

Answer 52

testes

Question 53

Which gland secretes lutenizing hormone and follicle-stimulating hormone?

Answer 53

anterior lobe of the pituitary gland

Question 54

What hormones does the anterior lobe of the pituitary gland secrete?

Answer 54

lutenizing hormone and follicle-stimulating hormone