Lecture 33 - Lipid Metabolism II Flashcards Preview

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Flashcards in Lecture 33 - Lipid Metabolism II Deck (50):
1

Fatty acid synthesis occurs in the (liver/all cells)

liver

2

Fatty acid break down occurs in (liver/all) cells

all

3

Enzymes for FA synthesis are localized in the (cytoplasm/mitochondria)

cytoplasm

4

Enzymes for FA degradation are localized in the (cytoplasm/mitochondria)

mitochondria

5

Acetyl-CoA is converted to _________ as the first step of FA synthesis.

A. malonyl-CoA
B. Acetoaceyl-CoA
C. Malonate
D. 3-D-hydroxybutyrate

A. malonyl-CoA

6

Synthesis of acetyl CoA for FAs occurs when ____ is produced in the mitochondria.

citrate

7

Citrate is formed in the mitochondria utilizing what two enzymes?

Pyruvate carboxylase (to form oxaloacetate)

PDH (to form acetyl-CoA)

8

Following citrate formation, it is shuttled to the mitochondria to be broken down into OAA and Acetyl-CoA. What enzyme is used for this breakdown?

A. malic enzyme
B. PDH
C. citrate lyase
D. pyruvate carboxylase

C. citrate lyase

9

For continued generation of Acetyl-Coa, malate is transformed back into pyruvate via ______, which also produces NADPH

malic enzyme

10

Addition of CO2 to acetyl-CoA produces ______ via acetyl-CoA carboxylase.

malonyl-CoA

11

Rate limiting step in FA synthesis

Acetyl-CoA to malonyl-CoA

12

(+) allosteric regulator of ACC

A. Insulin
B. glucagon
C. High carb diet
D. Citrate

D. citrate (precursor to the citrate-> OAA/Acetyl-CoA reaction)

13

(-) allosteric regulator of ACC

A. Citrate
B. Long chain FAs
C. Epinephrine
D. High carbohydrate diet

B. Long chain FAs

14

Control of ACC by dephosphorylation

insulin (high insulin indicates a large carbon pool, forcing dephosphorylation of ACC, producing more FAs)

15

Phosphorylation of ACC is caused by what compounds?

epinephrine and glucagon (indicate low energy state, no need to take "time" to produce FAs)

16

In the presence of low blood glucose, epinephrine and glucagon are released. These molecules inhibit acetyl-coa carboxylase, and prevent the formation of fatty acids. The Acetyl-CoA is instead utilized to make what compounds for energy?

Ketone bodies

17

Malonyl-CoA undergoes addition of two carbon fragments by the enzyme _____ until _____ is formed.

Fatty Acid Synthase Complex;

palmitate (16:0)

18

The fatty acid synthase complex contains what residue that is important for addition of CO2 to malonyl-CoA?

phosphopantetheine residue (PP)

19

PP of the acyl carrier protein on one FAS domain is attached to the _____ of the other FAS domain.

cysteinyl sulfhydryl group

20

The first step of FA synthesis is the _____ step.

A. condensation
B. reduction
C. Dehydration

A. condensation (adding of acetyl-CoA to malonyl-CoA to form acetoacetyl-CoA)

21

The second step of FA synthesis is the ___ step.

A. condensation
B. reduction
C. Dehydration

B. reduction (formation of ketoalcohol with production of NADP+)

22

The third step of FA synthesis is the ____ step.

A. condensation
B. reduction
C. Dehydration

C. dehydration (loss of water to form double bond)

23

The final step in FA synthesis is the ___ step.

A. condensation
B. reduction
C. Dehydration

B. Reduction (FA lengthened by two carbons)

24

FAS is stimulated by what allosteric effect?

Presence of phosphorylated sugars (indicates large amounts of carbohydrates)

25

Like ACC, FAS is also stimulated at the genetic level by ______.

high carbohydrate, low fat diets

26

Desaturation of FAs occurs with what three enzymes?

NADH-Cytochrome B5 reductase

Cytochrome B5

Stearoyl CoA desturase

27

De Novo synthesis of Triacylglycerols occurs in what two cells types?

Hepatocytes

Adipocytes

28

Hepatocytes utilize _____ to form G-3-P

A. glycerol
B. glucose
C. glycogen
D. DHAP

A. glycerol

29

Adipocytes utilize ___ to help form G-3-P in conjuction with hepatocytes.

A. glycerol
B. glucose
C. glycogen
D. DHAP

B. Glucose

30

Following formation ofo G-3-P, ___ is cleaved to form phosphatidic acid.

2x Acyl-CoA

31

G-3-P + Acyl-CoA forms ____

Phosphatidic acid

32

Following the removal of the inorganic phosphate from phosphatidic acid, a ___ is produced.

A. ketone
B. diacylglycerol
C. monoacylglycerol
D. triacylglyercol

B. diacylglycerol

33

The addition of acyl group to the DAG molecule in TAG synthesis produces _______.

TAG (triacylglycerol)

34

TAGs are packaged into _____ in the liver.

VLDL

35

Oxidation of arachidonic acid produces _______.

eicoisanoids

36

What are the 4 families of eicosanoids?

1) prostaglandins
2) prostaclycins
3) thromboxanes
4) leukotrienes

37

What two phospholipids are produced by reaction of a CTP-Head group with DAGs?

Phosphatidylcholine
Phosphatidylethanolalmine

38

What two phospholipids are produced from CDP-DAGs?

Phosphatidylinositol
Cardiollipin

39

Ethanolamine can be produced by ______ of phosphatidylserine.

decarboxylation

40

phosphatidyleserine can be formed adding _____ to ehtanolamine.

serine

41

Phosphatidyletanolamine can be methylated to form _____

phosphatidylcholine

42

Biosynthesis of cholesterol is regulated primarily by ______.

A. content of cholesterol in the PM
B. dietary intake
C. lysis of cell PMs

B. dietary intake

43

Approximately __ of cholesterol is produced by the liver daily.

1 gram

44

Acetyl-CoA is converted to mevalonate by ______.

HMG CoA Reductase (rate limiting step of cholesterol biosynthesis)

45

Production of the cholesterol ring begins at what intermediate?

A. mevalonate
B. dimethylallyl pyrophosphate
C. lanosterol
D. squalene

D. squalene

46

HMG CoA reductase forms HMGCoA by combining ____ and _____.

acetoacetyl-CoA

acetyl-CoA

*Similar as the formation of FAs, but utilizing a different enzyme

47

The major carbon source for fatty acid synthesis is ____.

A. TAGs
B. Cholesterol
C. Amino Acids
D. Dietary carbohydrates

D. Dietary carbohydrates

48

Which of the following contains the highest TAG content?

a. TAG
b. VLDL
c. LDL
D. HDL

a. TAG

49

Which of the following contains the largest amount of cholesterol?

a. TAG
b. VLDL
c. LDL
D. HDL

C. LDL

50

Which of the following contains the largest amount of protein/phospholipids?

a. TAG
b. VLDL
c. LDL
d. HDL

D. HDL