Biochem

Question 1

What is the rate limiting step for cholesterol synthesis?

Answer 1

HMG CoA reductase

(hydroxymethylglutaryl CoA)

Question 2

What inhibits HMG CoA reductase to lower cholesterol through competitive inhibtion?

Answer 2

Statins

Question 3

What are the 4 late stage inhibitors of cholesterol synthesis?

Answer 3

1. Antimycotics
2. Antiestrogens
3. Epileptogenic drug
4. Antipsychotic drugs

Question 4

Three Acetyl CoA form an ______.

Answer 4

IPP (isopentenyl pyrophospate) –> isoprenoid –> cholesterol/lipids

Question 5

What are 3 sources of Acetyl CoA?

Answer 5

pyruvate, fatty acis, amino acids (from mitochondria) and transported into cytoplasm

Question 6

What is the rate liming step of pathway that converts cholesterol to bile acids?

Answer 6

7-alpha hydroxylase

Question 7

Bile acid-binding resin drugs (ex. cholestyramine) do what?

Answer 7

Lower cholesterol via

1. Increasing rate of bile acid synthesis (7- alpha hydroxylase)
2. Increase the excretion of bile acids

Question 8

What are gallstones made of?

Answer 8

crystals of bile supersaturated w/ cholesterol

Question 9

Cytochrome P450 (CYPs) do what?

Answer 9

Detoxify pharmalogical agents (including statins)

Question 10

Citrus juices, grapefruit juice are?

Answer 10

CYP inhibitors –> increase statin levels (toxic)

Question 11

stimulating CYP =

Answer 11

decrese statin levels –> decrease in drug levels

Question 12

What do diseases of the liver generally cause?

Answer 12

Impairment of free exchange of material between hepatocytes and blood