Cholesterol

Question 1

Draw the steroid nucleus

Answer 1

ABCD rings

Question 2

The hydroxyl group in the cholesterol is located in what ring?

Answer 2

Ring A

Question 3

The hydrocarbon tail is located in the what ring

Answer 3

Ring D

Question 4

How many carbons are there in a cholesterol?

Answer 4

27 carbons

Question 5

The double bond of cholesterol happens in what carbons

Answer 5

C5-C6

Question 6

What are the derivatives of cholesterol?

Answer 6

1. Bile acids
2. Adrenal hormones
3. Sex hormones
4. Vitamin D

Question 7

What are the enzymes involved in converting cholestero to 7alpha hydroxycholesterol used in bile acid synthesis?

Answer 7

7alpha hydroxylase

Question 8

What are your primary bile acids?

Answer 8

1. Cholic acid

2. Chenodeoxycholic acid

Question 9

What are your secondary bile acids

Answer 9

1. Deoxycholic acid

2. Lithocholic acid

Question 10

What are your bile sats?

Answer 10

1. Conjugated taurine and glycine

Question 11

What is the substrate for cholesterol synthesis?

Answer 11

1. Acetyl Coa

Question 12

Which part of the cell does cholesterol synthesis occur?

Answer 12

1. Cytosol

2. Endoplasmic reticulum

Question 13

What is the rate limiting step in cholesterol synthesis?

Answer 13

1. HMG CoA to Mevalonate via HMG CoA reductase

Question 14

What enzyme converts acetyl CoA + Acetoacetyl CoA to HMG CoA

Answer 14

HMG CoA synthase

Question 15

HMG CoA is converted to mevalonate via this enzyme

Answer 15

HMG-CoA reductase

Needs 2 NADPH

Question 16

Mevalonate is converted to what intermediate in cholesterolm synthesis??

Answer 16

Isopentenyl pyrophosphate C5

C10 = geranyl pyrophosphate

C15 = farnesyl pyrophosphate

Question 17

Squalene is formed from combining what intermediate?

Answer 17

Farnesyl pyrophosphate (C15)

Question 18

What enzyme creates lanosterol from squalene?

Answer 18

cyclase

Question 19

What is the immediate precursol of cholesterol?

Answer 19

Lanosterol

Question 20

Product inhibition of cholesterol synthesis is possible due to what transcription factor?

Answer 20

Sterol regulatory element binding protein (SREBP)

Question 21

In cholesterol synthesis, a dephosphorylated enzyme is ___ (active/inactive)

Answer 21

active

Question 22

What hormones increases HMG-CoA reductase?

Answer 22

1. Insulin

2. Thyroid hormone

Question 23

What hormones decreases HMG-CoA reductase?

Answer 23

1. Glucagon

2. Glucocorticoids

Question 24

Which part of the cholesterol structure that cant be metabolized by humans?

Answer 24

cholesterol ring

Question 25

Bacteria in the intestines convert cholesterol to what compounds?

Answer 25

1. Coprostanol | 2. Cholestanol

Question 26

[diagnose] deficiency in 7-dehydrocholesterio reductase

Answer 26

Smith-Lemli-Opitz Syndrome

Question 27

[diagnose] low plasma cholestero and elevated 7-dehydrocholesterol dysmorphic facial features, microcephaly, mental retardation, congenital heart disease, malformations, still born

Answer 27

Smith-Lemli-Opitz syndrome

Question 28

What is the most common enzyme deficiency in congenital adrenal hyperplasia

Answer 28

21-apha hydroxylase deficiency

Question 29

[Diagnosis] Overproduction of androgen, musculinization of external genitalia in females and early virilization in males

Answer 29

21-alpha hydroxylase deficiency

Question 30

[Diagnosis] what enzyme is deficient when patient has a decreased serum cortisol, aldosterone, corticosterone

Answer 30

11-beta1-hydroxylase deficiency

Question 31

[Diagnosis] "low renin" hypertension

Answer 31

11 beta 1 hydroxylase deficiency

Question 32

[Diagnosis] ___ autoimmune destruction of adrenal cortex

Answer 32

addison disease Addison = adrenal destruction

Question 33

[Lipid transport] The core of plasma lipoprotein is made of what type of lipids?

Answer 33

neutral lipids

Question 34

[Lipid transport] Example of peripheral apoprotein

Answer 34

Apo C

Question 35

[Lipid transport] example of integral apoprotein

Answer 35

Apo B

Question 36

[Lipoprotein] largest diameter, lowest density, highest TAG

Answer 36

chylomicron

Question 37

[Lipoprotein] highest cholesterol content

Answer 37

LDL

Question 38

[Lipoprotein] highest protein content

Answer 38

HDL Density increases as you lower lipid content

Question 39

[Apoprotein] Found mainly in HDL

Answer 39

Apo A-1 structural component of HDL

Question 40

[Apoprotein] co-factor of lecithin:cholesterol acyl transferase

Answer 40

Apo A-1

Question 41

[Apoprotein] mediates assembly and secretion of VLDL

Answer 41

ApoB 100

Question 42

[Apoprotein] structural protein of VLDL, IDL, LDL

Answer 42

ApoB 100

Question 43

[Apoprotein] mediates secretion fo chylomicrons from small intestines

Answer 43

Apo B-48

Question 44

[Apoprotein] co factor of lipoprotein lipase

Answer 44

Apo C-II

Question 45

[Apoprotein] mediates uptake of chylomicron remnants and IDLs

Answer 45

Apo E

Question 46

[Hyperlipoproteinemia] high TAG, low LDL, Low HDL Xanthomas, recurrent pancreatitis, hepatosplenomegaly, NO INCREASED RISK OF CAD

Answer 46

Type I - Familial lipoprotein lipase deficiency due to deficient lipoprotein lipase OR apo CII

Question 47

[Hyperlipoproteinemia] High LDL, high cholesterol

Answer 47

Type IIa - hypercholesteriolemia Defective LDL receptor

Question 48

[Hyperlipoproteinemia] Hypercholesterolemia Xanthomas Atherosclerosis defective Apo E

Answer 48

Type III familial dysbetalipoproteinemia

Question 49

[Hyperlipoproteinemia] High TAG, high VLDL Subnormal LDL subnormal HDL Associated with coronary disease, type 2 DM, obesity, alcoholism

Answer 49

Type IV Familial hypertriacylglycerolemia due to overproduction of VLDL

Question 50

[Hyperlipoproteinemia] Thrombosis due to inhibition of fibrinolysis

Answer 50

Familial lipoprotein A excess elevated LpA

Question 51

What lipoprotein which is nearly identical to LDL?

Answer 51

lipoprotein A

Question 52

[Hyperlipoproteinemia] high HDL

Answer 52

Familial hyperalphaproteinemia

Question 53

[Hypolipoproteinemia] low TAG, accumulation of TAG in liver and intestine can be treated using large doses of fat soluble vitamins (vitamin E)

Answer 53

Abetalipoproteinemia - defect in loading of Apo B with lipid

Question 54

[Hypolipoproteinemia] high TAG due to absence of Apo CII leading to inactive LPL; atherosclerosis in elderly

Answer 54

Familial alpha-lipoprotein deficiency low or near absence of HDL

Question 55

[Chylomicron] From the intestine to the capillaries

Answer 55

1. Nascent chylomicron (Apo B48) 2. HDL is added (Apo CII, Apo E) 3. Chylomicron in capillaries (Apo B 48, Apo C-II, Apo E)

Question 56

[Chylomicron] from the capillaries to the liver

Answer 56

1. TAG removed from chylomicron by lipoprotein lipase (activated by Apo CII) 2. Apo CII returned to HDL 3. Chylomicron remnant goes to the liver (Apo E, Apo B 48) 4. Apo E binds to receptor in liver

Question 57

[VLDL] from liver to capillaries

Answer 57

1. Nascent VLDL (Apo B 100) 2. HDL is added (Apo CII, Apo E) 3. VLDL in capillaries (Apo B100, Apo C-II, ApoE)

Question 58

[VLDL] From capillaries to extrahepatic tissue liver

Answer 58

1. VLDL (Apo B100, Apo E, Apo C-II) 2. Lipoprotein lipase degrades TAG (activated by Apo CII) 3. Apo CII and APO E are returned to HDL 4. Apo B-100 binds to extrahepatic tisse and liver

Question 59

[HDL] what is enzyme assimilates cholesterol in VLDL to be used by HDL?

Answer 59

CETP

Question 60

[HDL] What enzyme releases cholesterol esters in the liver?

Answer 60

ACAT

Question 61

[HDL] What enzyme releases cholesterol esters from the cell?

Answer 61

LCAT