Question 1

How may of the carbon atoms from stearic acid may contribute, through cellular metabolism, to the net synthesis of glucose?

Accepted Answer

A)   18
B)   17
C)   6
D)   3
E)   0F) None of the above
G) B) and E)

Question 2

The enzyme primarily responsible for generating acetyl-CoA in the cytoplasm is

Accepted Answer

A)   ATP-citrate synthase.
B)   malic enzyme.
C)   malate dehydrogenase.
D)   ATP-citrate lyase.
E)   acetyl-CoA carnitine transferase.F) B) and C)
G) B) and E)

Question 3

The reductive steps in fatty acids synthesis are carried out by

Accepted Answer

A)   FADH2 and NADH
B)   NADH
C)   NADH and NADPH
D)   NADPH
E)   NADPH and FADH2F) D) and E)
G) A) and E)

Question 4

True statements about de novo fatty acid synthesis include

Accepted Answer

A)   It utilizes acetyl CoA from carbohydrates and occurs in the liver and adipocyte inner mitochondrial matrix.
B)   The rate limiting step involves a reaction in which acetyl CoA accepts a one carbon group from another acetyl CoA to form malonyl CoA.
C)   Acetyl CoA carboxylase is active only in its multimeric form which contains biotin in a N-carboxybiotin-enzyme complex.
D)   Fatty acid synthase is a complex enzyme in humans which is active as a homodimer. Each round of synthesis adds two carbons from malonyl-CoA to the methyl end of the fatty acid chain. The final product contains the original two carbons
E)   The acyl carrier protein (ACP)  in the fatty acid synthase enzyme contains a biotin moiety esterified to a hydroxyl group of serine to provide the sulfhydryl group onto which the growing fatty acid chain is always attached.F) All of the above
G) C) and E)

Question 5

Position number one in the triglycerides of man is filled by a fatty acid residue that is

Accepted Answer

A)   always saturated.
B)   usually saturated.
C)   always unsaturated.
D)   usually unsaturated.
E)   equally likely to be saturated or unsaturated.F) C) and E)
G) None of the above

Question 6

Which of the following is the most active positive effector of acetyl-CoA carboxylase?

Accepted Answer

A)   citrate
B)   oxaloacetate
C)   malonyl-CoA
D)   ADP
E)   pyruvateF) A) and E)
G) A) and D)

Question 7

Fatty acid synthesis is primarily controlled by regulation of

Accepted Answer

A)   citrate synthase.
B)   pyruvate carboxylase.
C)   glucose 6-phosphate dehydrogenase.
D)   beta-keto fatty acyl ACP reductase.
E)   acetyl-CoA carboxylase.F) A) and C)
G) C) and E)

Question 8

Fatty acid synthase

Accepted Answer

A)   produces oleic acid by skipping a reductive step.
B)   can produce fatty acid with an odd number of carbon atoms.
C)   produces mainly palmitate as the product.
D)   is found in the mitochondria of cells.
E)   is found in the adipose tissue but not in the liver.F) A) and B)
G) B) and C)

Question 9

Which one of the following is an example of precursor (feedforward)  activation? The effect of

Accepted Answer

A)   palmityl CoA on acetyl CoA carboxylase.
B)   citrate on acetyl CoA carboxylase.
C)   insulin on hormone-sensitive lipase.
D)   malonyl CoA on carnitine acyl transferase I.E) A) and B)
F) C) and D)

Question 10

In humans, fatty acids

Accepted Answer

A)   can be synthesized from excess dietary carbohydrates or protein.
B)   are not required at all in the diet.
C)   containing double bonds cannot be synthesized.
D)   must be supplied entirely in the diet.
E)   other than palmitate, must be supplied in the diet.F) C) and E)
G) C) and D)

Question 11

The most prevalent saturated fatty acid in animal fat is

Accepted Answer

A)   caprylic.
B)   lauric.
C)   myristic.
D)   palmitic.
E)   stearic.F) B) and C)
G) B) and E)

Question 12

The elongation of fatty acids occurs

Accepted Answer

A)   only in the cytosol.
B)   only in microsomes.
C)   in both mitochondria and microsomes.
D)   only in mitochondria.
E)   only in the brain.F) A) and B)
G) C) and D)

Question 13

The mobilization of triglyceride fatty acids from adipose tissue and their subsequent oxidation by muscle mitochondria involves all of the following EXCEPT

Accepted Answer

A)   serum albumin.
B)   carnitine.
C)   acyl carrier protein.
D)   hormone sensitive lipase.
E)   acyl-CoA synthetase.F) A) and D)
G) A) and B)

Question 14

Lipids are the most efficient forms of biologically stored energy because they are

Accepted Answer

A)   highly insoluble.
B)   highly soluble.
C)   highly oxidized.
D)   highly reduced.
E)   converted directly to ATP.F) B) and C)
G) None of the above

Question 15

Functional mammalian fatty acid synthase is composed of:

Accepted Answer

A)   A dimer of identical subunits, with each subunit catalytically functioning independently
B)   A dimer of identical subunits, with the subunits forming two catalytically active sites in the region where the subunits interface.
C)   Both
D)   NeitherE) B) and D)
F) A) and B)

Question 16

De novo fatty acid biosynthesis occurs in the

Accepted Answer

A)   mitochondria.
B)   endoplasmic reticulum (microsomal fraction) .
C)   lysosomes.
D)   cytosol.
E)   nucleus.F) B) and E)
G) A) and B)

Question 17

How may of the carbon atoms from stearic acid may contribute, through cellular metabolism, to the net synthesis of glucose?

Accepted Answer

A)   18
B)   17
C)   6
D)   3
E)   0F) A) and E)
G) C) and D)

Question 18

Which of the groups below contains two compounds that are parts of coenzymes involved in the beta-oxidation of fatty acids?

Accepted Answer

A)   Vitamin D and pantothenic acid
B)   biotin and folic acid
C)   Niacin and riboflavin
D)   Pyridoxine and thiamine
E)   Choline and carnitineF) A) and D)
G) D) and E)

Question 19

Which of the following statements about triacylglycerols is not true?

Accepted Answer

A)   Triacylglycerols are the major storage form of fatty acids.
B)   Triacylglycerols are transported in the blood bound to albumin.
C)   Triacylglycerols can be hydrolyzed to provide a gluconeogenic substrate.
D)   Triacylglycerols contain 3 fatty acids esterified to a glycerol backbone.
E)   Triacylglycerols are an efficient storage form of energy.F) None of the above
G) A) and B)

Question 20

The synthesis of fatty acids by the de novo pathway from acetyl-CoA

Accepted Answer

A)   proceeds by the reversal of beta-oxidation.
B)   occurs primarily in mitochondria.
C)   requires NADPH, ATP and bicarbonate.
D)   is increased during fasting.
E)   utilizes acetoacetyl-CoA as substrate for beta-ketoacyl reductase.F) D) and E)
G) All of the above

Exam 17: Lipid Metabolism I: Synthesis, Storage, and Utilization of Fatty Acids and Triacylglycerols

How may of the carbon atoms from stearic acid may contribute, through cellular metabolism, to the net synthesis of glucose?

Correct AnswerverifiedShow Answer

De novo fatty acid biosynthesis occurs in the

Correct AnswerverifiedShow Answer

How may of the carbon atoms from stearic acid may contribute, through cellular metabolism, to the net synthesis of glucose?

Correct AnswerverifiedShow Answer

Lipids are the most efficient forms of biologically stored energy because they are

Correct AnswerverifiedShow Answer

The most prevalent saturated fatty acid in animal fat is

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The reductive steps in fatty acids synthesis are carried out by

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Fatty acid synthase

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The enzyme primarily responsible for generating acetyl-CoA in the cytoplasm is

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The synthesis of fatty acids by the de novo pathway from acetyl-CoA

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Functional mammalian fatty acid synthase is composed of:

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Which of the following statements about triacylglycerols is not true?

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In humans, fatty acids

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Which of the following is the most active positive effector of acetyl-CoA carboxylase?

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Position number one in the triglycerides of man is filled by a fatty acid residue that is

Correct AnswerverifiedShow Answer

The elongation of fatty acids occurs

Correct AnswerverifiedShow Answer

True statements about de novo fatty acid synthesis include

Correct AnswerverifiedShow Answer

Fatty acid synthesis is primarily controlled by regulation of

Correct AnswerverifiedShow Answer

The mobilization of triglyceride fatty acids from adipose tissue and their subsequent oxidation by muscle mitochondria involves all of the following EXCEPT

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Which one of the following is an example of precursor (feedforward) activation? The effect of

Correct AnswerverifiedShow Answer

Which of the groups below contains two compounds that are parts of coenzymes involved in the beta-oxidation of fatty acids?

Correct AnswerverifiedShow Answer

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