Question 1

In adult mammals fatty acid synthesis largely occurs in the cytosol of liver cells and adipocytes.

Accepted Answer

A) True 
 B)False

Question 2

Animals use a type I fatty acid synthesis system FAS (I) while bacteria use a type II fatty acid synthesis system FAS (II).

Accepted Answer

A) True 
 B)False

Question 3

Lysosomal storage diseases occur when mutations cause defects in .

Accepted Answer

A)  sphingolipid biosynthesis enzymes 
B)  sphingolipid degradation enzymes 
C)  lysosome formation 
D)  formation of N-acetylgalactosamine derivatives 
A)  sphingolipid biosynthesis enzymes 
B)  sphingolipid degradation enzymes 
C)  lysosome formation 
D)  formation of N-acetylgalactosamine derivatives

Question 4

Which of the following is mis-matched?

Accepted Answer

A)  bile salts - intestinal absorption of lipids 
B)  b-estradiol - sex characteristics 
C)  cholesterol - membrane fluidity 
D)  squalene - lipid vitamin 
A)  bile salts - intestinal absorption of lipids 
B)  b-estradiol - sex characteristics 
C)  cholesterol - membrane fluidity 
D)  squalene - lipid vitamin

Question 5

Which statement is false about polyunsaturated fatty acids?

Accepted Answer

A)  They have both odd-numbered and even-numbered double bonds. 
B)  Their synthesis is more energy-efficient than the synthesis of saturated fatty acids. 
C)  Some double bonds are rearranged during their degradation. 
D)  They require D3, D2-enoyl-CoA isomerase for their oxidation. 
A)  They have both odd-numbered and even-numbered double bonds. 
B)  Their synthesis is more energy-efficient than the synthesis of saturated fatty acids. 
C)  Some double bonds are rearranged during their degradation. 
D)  They require D3, D2-enoyl-CoA isomerase for their oxidation.

Question 6

Most of the lipids in the diets of mammals are free fatty acids.

Accepted Answer

A) True 
 B)False

Question 7

A biotin-dependent enzyme is responsible for catalyzing the carboxylation of acetyl CoA.

Accepted Answer

A) True 
 B)False

Question 8

High levels of VLDLs have been found to have a protective effect against atherosclerosis.

Accepted Answer

A) True 
 B)False

Question 9

Why is it undesirable to have high concentrations of free fatty acids in cells?

Accepted Answer

A)  They are unstable, free radicals that can react to form toxic substances. 
B)  They polymerize easily and can cause the cytosol to become too gel-like. 
C)  They are amphipathic and act as detergents that can degrade membranes. 
D)  They inhibit the uptake of pyruvate by mitochondria. 
A)  They are unstable, free radicals that can react to form toxic substances. 
B)  They polymerize easily and can cause the cytosol to become too gel-like. 
C)  They are amphipathic and act as detergents that can degrade membranes. 
D)  They inhibit the uptake of pyruvate by mitochondria.

Question 10

Which enzyme requires adenosylcobalamin as a cofactor?

Accepted Answer

A)  carnitine acyl transferase I 
B)  methylmalonyl-CoA mutase 
C)  enoyl-CoA hydratase 
D)  propionyl-CoA carboxylase 
A)  carnitine acyl transferase I 
B)  methylmalonyl-CoA mutase 
C)  enoyl-CoA hydratase 
D)  propionyl-CoA carboxylase

Question 11

The largest lipoproteins are the .

Accepted Answer

A)  chylomicrons 
B)  VLDLs 
C)  LDLs 
D)  HDLs 
A)  chylomicrons 
B)  VLDLs 
C)  LDLs 
D)  HDLs

Question 12

The elongation of fatty acids is a repetition of three reactions adding carbons from after each cycle until completion.

Accepted Answer

A)  malonyl CoA 
B)  malonyl ACP 
C)  acetyl CoA 
D)  acetyl ACP 
A)  malonyl CoA 
B)  malonyl ACP 
C)  acetyl CoA 
D)  acetyl ACP

Question 13

Cytosolic HMG-CoA is used for ketone body synthesis.

Accepted Answer

A) True 
 B)False

Question 14

Which bonds of the triacylglycerol shown are hydrolyzed by pancreatic lipase?

Accepted Answer

A)  The carbon-carbon bonds between atoms 1,2 and 3. 
B)  The ester bond at carbon 2 only. 
C)  The bonds between the carbonyl carbons 4 and 6 and the first carbon of the hydrocarbon chains. 
D)  The ester bonds at carbons 1 and 3 only. 
A)  The carbon-carbon bonds between atoms 1,2 and 3. 
B)  The ester bond at carbon 2 only. 
C)  The bonds between the carbonyl carbons 4 and 6 and the first carbon of the hydrocarbon chains. 
D)  The ester bonds at carbons 1 and 3 only.

Question 15

Ketone bodies are normally broken down in the liver in preparation for excretion.

Accepted Answer

A) True 
 B)False

Question 16

Which of the following is true for carboxylation of acetyl CoA?

Accepted Answer

A)  In animals and yeast, it requires three separate protein subunits. 
B)  It is a metabolically reversible reaction. 
C)  In bacteria, it is catalyzed by a bifunctional enzyme. 
D)  The regulatory enzyme is acetyl-CoA carboxylase. 
A)  In animals and yeast, it requires three separate protein subunits. 
B)  It is a metabolically reversible reaction. 
C)  In bacteria, it is catalyzed by a bifunctional enzyme. 
D)  The regulatory enzyme is acetyl-CoA carboxylase.

Question 17

An increase in glucagon levels activates the enzyme which catalyzes malonyl CoA synthesis in the liver.

Accepted Answer

A) True 
 B)False

Question 18

Which of the following is a true statement for fatty acid synthesis?

Accepted Answer

A)  It occurs in the mitochondria. 
B)  The reducing power for synthesis is supplied by NAD+ and ubiquinone. 
C)  Both A and B 
D)  None of the above 
A)  It occurs in the mitochondria. 
B)  The reducing power for synthesis is supplied by NAD+ and ubiquinone. 
C)  Both A and B 
D)  None of the above

Question 19

Phosphatidate is an intermediate in the synthesis of .

Accepted Answer

A)  triacylglycerols and glycerophospholipids 
B)  glycerophospholipids only 
C)  sphingolipids 
D)  cholesterol 
A)  triacylglycerols and glycerophospholipids 
B)  glycerophospholipids only 
C)  sphingolipids 
D)  cholesterol

Question 20

During the fed state, which of the following occurs)?

Accepted Answer

A)  insulin inhibition of the hydrolysis of stored triacylglycerols 
B)  insulin stimulation of malonyl CoA formation 
C)  allosteric inhibition of carnitine acyltransferase I 
D)  All of the above 
A)  insulin inhibition of the hydrolysis of stored triacylglycerols 
B)  insulin stimulation of malonyl CoA formation 
C)  allosteric inhibition of carnitine acyltransferase I 
D)  All of the above

Exam 16: Lipid Metabolism

In adult mammals fatty acid synthesis largely occurs in the cytosol of liver cells and adipocytes.

Animals use a type I fatty acid synthesis system FAS (I) while bacteria use a type II fatty acid synthesis system FAS (II).

Lysosomal storage diseases occur when mutations cause defects in .

Which of the following is mis-matched?

Which statement is false about polyunsaturated fatty acids?

Most of the lipids in the diets of mammals are free fatty acids.

A biotin-dependent enzyme is responsible for catalyzing the carboxylation of acetyl CoA.

High levels of VLDLs have been found to have a protective effect against atherosclerosis.

Why is it undesirable to have high concentrations of free fatty acids in cells?

Which enzyme requires adenosylcobalamin as a cofactor?

The largest lipoproteins are the .

The elongation of fatty acids is a repetition of three reactions adding carbons from after each cycle until completion.

Cytosolic HMG-CoA is used for ketone body synthesis.

Which bonds of the triacylglycerol shown are hydrolyzed by pancreatic lipase?

Ketone bodies are normally broken down in the liver in preparation for excretion.

Which of the following is true for carboxylation of acetyl CoA?

An increase in glucagon levels activates the enzyme which catalyzes malonyl CoA synthesis in the liver.

Which of the following is a true statement for fatty acid synthesis?

Phosphatidate is an intermediate in the synthesis of .

During the fed state, which of the following occurs)?

Introduction to Biochemistry

Water

Amino Acids and the Primary Structures of Proteins

Proteins: Three-Dimensional Structure and Function

Properties of Enzymes

Mechanisms of Enzymes

Coenzymes and Vitamins

Carbohydrates

Lipids and Membranes

Introduction to Metabolism

Glycolysis

Gluconeogenesis, the Pentose Phosphate Pathway, and Glycogen Metabolism

The Citric Acid Cycle

Electron Transport and Oxidative Phosphorylation

Photosynthesis

Amino Acid Metabolism

Nucleotide Metabolism

Nucleic Acids

Dna Replication, Repair, and Recombination

Transcription and Rna Processing

Protein Synthesis

Recombinant Dna Technology

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