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Biochemistry > Lecture 33 - Lipid Metabolism II > Flashcards

Lecture 33 - Lipid Metabolism II Flashcards

(50 cards)

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1
Q

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

A

liver

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2
Q

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

A

all

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3
Q

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

A

cytoplasm

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4
Q

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

A

mitochondria

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5
Q

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

A. malonyl-CoA

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6
Q

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

A

citrate

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7
Q

Citrate is formed in the mitochondria utilizing what two enzymes?

A

Pyruvate carboxylase (to form oxaloacetate)

PDH (to form acetyl-CoA)

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8
Q

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

A

C. citrate lyase

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9
Q

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

A

malic enzyme

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10
Q

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

A

malonyl-CoA

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11
Q

Rate limiting step in FA synthesis

A

Acetyl-CoA to malonyl-CoA

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12
Q

(+) allosteric regulator of ACC

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

A

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

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13
Q

(-) allosteric regulator of ACC

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

A

B. Long chain FAs

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14
Q

Control of ACC by dephosphorylation

A

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

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15
Q

Phosphorylation of ACC is caused by what compounds?

A

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

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16
Q

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?

A

Ketone bodies

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17
Q

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

A

Fatty Acid Synthase Complex;

palmitate (16:0)

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18
Q

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

A

phosphopantetheine residue (PP)

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19
Q

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

A

cysteinyl sulfhydryl group

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20
Q

The first step of FA synthesis is the _____ step.

A. condensation
B. reduction
C. Dehydration

A

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

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21
Q

The second step of FA synthesis is the ___ step.

A. condensation
B. reduction
C. Dehydration

Study These Flashcards
A

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

22
Q

The third step of FA synthesis is the ____ step.

A. condensation
B. reduction
C. Dehydration

Study These Flashcards
A

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

23
Q

The final step in FA synthesis is the ___ step.

A. condensation
B. reduction
C. Dehydration

Study These Flashcards
A

B. Reduction (FA lengthened by two carbons)

24
Q

FAS is stimulated by what allosteric effect?

Study These Flashcards
A

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

Biochemistry (43 decks)

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