Which of the following is not required in the synthesis of fatty acids?
A) Acetyl-CoA
B) Biotin
C) HCO3
D) Malonyl-CoA
E) NADH
E
Which of the following is not true of the reaction producing malonyl-CoA during fatty acid synthesis?
A) It is stimulated by citrate.
B) It requires acyl carrier protein (ACP).
C) It requires CO2
D) One mole of ATP is converted to ADP + Pi for each malony
B
If malonyl-CoA is synthesized from 14CO2 and unlabeled acetyl-CoA, and the labeled malonate is then used for fatty acid synthesis, the final product (fatty acid) will have radioactive carbon in:
A) every C.
B) every even-numbered C-atom.
C) every odd-numb
D
Which one of the following statements best applies to synthesis of fatty acids in E. coli extracts?
A) Acyl intermediates are thioesters of a low molecular weight protein called acyl carrier protein.
B) CO2
C) Reducing equivalents are provided by NADPH
D)
E
In comparing fatty acid biosynthesis with ? oxidation of fatty acids, which of the following statements is incorrect?
A) A thioester derivative of crotonic acid (trans-2-butenoic acid) is an intermediate in the synthetic path, but not in the degradative p
D
Enzymes that catalyze the synthesis of long chain fatty acids in vertebrate cells:
A) act as seven separate proteins.
B) are encoded in mitochondrial genes.
C) are localized in the mitochondrial matrix.
D) are part of a single polypeptide chain containing
D
Which of the following is not true of the fatty acid synthase and the fatty acid ?-oxidation systems?
A) A derivative of the vitamin pantothenic acid is involved.
B) Acyl-CoA derivatives are intermediates.
C) Double bonds are oxidized or reduced by pyridi
E
The rate-limiting step in fatty acid synthesis is:
A) condensation of acetyl-CoA and malonyl-CoA.
B) formation of acetyl-CoA from acetate.
C) formation of malonyl-CoA from malonate and coenzyme A.
D) the reaction catalyzed by acetyl-CoA carboxylase.
E) th
D
Which of the following is not true of the fatty acid elongation system of vertebrate cells?
A) It involves the same four-step sequence seen in the fatty acid synthase complex.
B) It is located in the smooth endoplasmic reticulum.
C) It produces stearoyl-C
E
Which of these can be synthesized by plants but not by humans?
A) Linoleate [18:2(?
B) Palmitate (16:0)
C) Phosphatidylcholine
D) Pyruvate
E) Stearate (18:0)
A
The enzyme system for adding double bonds to saturated fatty acids requires all of the following except:
A) a mixed-function oxidase.
B) ATP.
C) cytochrome b5
D) molecular oxygen (O2
E) NADPH.
.
).
B
Which of these statements about eicosanoid synthesis is true?
A) An early step in the path to thromboxanes is blocked by ibuprofen.
B) Arachidonate is derived mainly by hydrolysis of triacylglycerols.
C) Aspirin acts by blocking the synthesis of arachidon
A
The biosynthesis of triacylglycerols from acetate occurs mainly in:
A) animals but not in plants.
B) humans after ingestion of excess carbohydrate.
C) humans with low carbohydrate intake.
D) plants but not in animals.
E) none of the above.
B
The synthesis of both glycerophospholipids and triacylglycerols involves:
A) CDP-choline.
B) CDP-diacylglycerol.
C) phosphatidate phosphatase.
D) phosphatidic acid.
E) phosphoethanolamine.
D
Which of these statements about triacylglycerol synthesis is correct?
A) Humans can store more energy in glycogen than in triacylglycerols.
B) Insulin stimulates conversion of dietary carbohydrate into triacylglycerols.
C) It is not a hormone-sensitive pr
B
A strategy that is not employed in the synthesis of phospholipids is:
A) condensation of CDP-alcohol with diacylglycerol.
B) condensation of CDP-diacylglycerol with alcohol.
C) condensation of CDP-diacylglycerol with CDP-alcohol.
D) exchange of free alcoh
C
All glycerol-containing phospholipids are synthesized from:
A) cardiolipin
B) ceramide.
C) gangliosides.
D) mevalonate.
E) phosphatidic acid
E
In E. coli the synthesis of phosphatidylethanolamine directly involves:
A) acyl carrier protein.
B) biotin.
C) CDP-choline.
D) phosphatidylglycerol.
E) serine.
E
In the synthesis of phosphatidylcholine from phosphatidylethanolamine, the methyl group donor is:
A) a tetrahydrofolate derivative.
B) choline.
C) methanol.
D) S-adenosylmethionine (adoMet).
E) serine.
D
Palmitoyl-CoA, , is a direct precursor of:
A) cholesterol.
B) malonyl-CoA.
C) mevalonate
D) sphingosine.
E) squalene.
D
CDP-diglyceride is not involved in the biosynthesis of:
A) phosphatidylcholine.
B) phosphatidylethanolamine
C) phosphatidylglycerol.
D) phosphatidylserine.
E) sphingomyelin.
E
Which of the following is true of sphingolipid synthesis?
A) All of the carbon atoms of palmitate and serine are incorporated into sphingosine.
B) CDP-sphingosine is the activated intermediate.
is produced during the synthesis of ceramide from palmitate a
C
Which of the following is not an intermediate in the synthesis of lanosterol from acetyl-CoA?
A) Isopentenyl pyrophosphate
B) Malonyl-CoA
C) Mevalonate
D) Squalene
E) ?-Hydroxy-?-methylglutaryl-CoA (HMG-CoA)
B
Cholesterol is synthesized from:
A) acetyl-CoA.
B) choline.
C) lipoic acid.
D) malate.
E) oxalate.
A
A 30-carbon precursor of the steroid nucleus is:
A) farnesyl pyrophosphate.
B) geranyl pyrophosphate.
C) isopentenyl pyrophosphate.
D) lysolecithin.
E) squalene.
E
Which of these statements about cholesterol synthesis is true?
A) Cholesterol is the only known natural product whose biosynthesis involves isoprene units.
B) Only half of the carbon atoms of cholesterol are derived from acetate.
C) Squalene synthesis fro
C
Which of the following is derived from a sterol?
A) Bile salts
B) Gangliosides
C) Geraniol
D) Phosphatidylglycerol
E) Prostaglandins
A
Which of these statements about the regulation of cholesterol synthesis is not true?
A) Cholesterol acquired in the diet has essentially no effect on the synthesis of cholesterol in the liver.
B) Failure to regulate cholesterol synthesis predisposes human
A
Which of these compounds is not synthesized by a pathway that includes isoprene precursors?
A) Natural rubber
B) Plastoquinone
C) Vitamin A
D) Vitamin B12
E) Vitamin K
D