Question 1

List in order the three most abundant molecule types found in an HDL.

Accepted Answer

HDLs are composed of proteins

Question 2

Which enzyme activates acetyl-CoA so that it can be added to the growing fatty acid chain during the synthesis of palmitate?

Accepted Answer

A)  acetyl-CoA carboxylase 
B)  fatty acyl-CoA synthase 
C)  acyl-CoA dehydrogenase 
D)  fatty acid synthase 
A)  acetyl-CoA carboxylase 
B)  fatty acyl-CoA synthase 
C)  acyl-CoA dehydrogenase 
D)  fatty acid synthase

Question 3

The rate-limiting step of cholesterol synthesis involves controlling the fate of HMG-CoA. What other pathways is HMG-CoA involved in?

Accepted Answer

HMG-CoA could be con

Question 4

Explain how humans can create oleoyl-CoA (18:1 $\Delta$9) from stearoyl-CoA (18:0).

Accepted Answer

By using a

Question 5

What are the known components of atherosclerotic plaques?

Accepted Answer

Cholesterol, various

Question 6

Starting from the 6C fatty acyl-CoA molecule shown below, draw the reactants and products, including all cofactors used for one round of the $\beta$-oxidation pathway and list the enzyme
types involved in each step.

Accepted Answer

The answer of Starting from the 6C fatty acyl-CoA molecule...

Question 7

Which of the following do $\beta$-oxidation and fatty acid synthesis have in common?

Accepted Answer

A)  the presence of an oxidized fatty acyl $\beta$-carbon with a hydroxyl or carbonyl group as a pathway intermediate 
B)  their cellular location 
C)  their use of NADH 
D)  the number of enzymes involved in the pathways 
A)  the presence of an oxidized fatty acyl $\beta$-carbon with a hydroxyl or carbonyl group as a pathway intermediate 
B)  their cellular location 
C)  their use of NADH 
D)  the number of enzymes involved in the pathways

Question 8

List the four key steps in the synthesis of cholesterol.

Accepted Answer

(1) Three acetyl-coA molecules are combi

Question 9

List the primary three physiological roles played by cholesterol or cholesterol derivatives.

Accepted Answer

Cholesterol is converted to bile acids f

Question 10

The $\beta$-oxidation of mono- and polyunsaturated fatty acids

Accepted Answer

A)  requires an extra cycle through the pathway. 
B)  involves the reduction of the double bonds and then the continuation of $\beta$-oxidation. 
C)  yields succinyl-CoA. 
D)  involves isomerization and in some cases reduction of the double bonds before the continuation of $\beta$-oxidation. 
A)  requires an extra cycle through the pathway. 
B)  involves the reduction of the double bonds and then the continuation of $\beta$-oxidation. 
C)  yields succinyl-CoA. 
D)  involves isomerization and in some cases reduction of the double bonds before the continuation of $\beta$-oxidation.

Question 11

Which fatty acid can be synthesized from scratch in humans by desaturase enzymes?

Accepted Answer

A) 20:4,$\Delta$5,8,11,14 
B)  18:2, $\Delta$9,13 
C)  20:2, $\Delta$6,9  
D)  16:2, $\Delta$9,11 
A) 20:4,$\Delta$5,8,11,14 
B)  18:2, $\Delta$9,13 
C)  20:2, $\Delta$6,9  
D)  16:2, $\Delta$9,11

Question 12

LDLs are referred to as "bad cholesterol" because

Accepted Answer

A)  they are the blood serum particle with the highest concentration of cholesterol. 
B)  they contain cholesterol that is not as easily degraded. 
C)  their cholesterol has no specific cellular purpose other than to form plaques. 
D)  LDL levels surge after meals high in fat. 
A)  they are the blood serum particle with the highest concentration of cholesterol. 
B)  they contain cholesterol that is not as easily degraded. 
C)  their cholesterol has no specific cellular purpose other than to form plaques. 
D)  LDL levels surge after meals high in fat.

Question 13

Which enzyme catalyzes the rate-limiting step of cholesterol synthesis?

Accepted Answer

A)  cholesterol synthase 
B)  HMG-CoA reductase 
C)  thiolase 
D)  HMG-CoA synthase 
A)  cholesterol synthase 
B)  HMG-CoA reductase 
C)  thiolase 
D)  HMG-CoA synthase

Question 14

What are the different roles played the acyl carrier protein (ACP) and the ketoacyl synthase (KS) domain during fatty acid synthesis?

Accepted Answer

A)  The ACP carries the growing fatty acid chain more than the KS domain. 
B)  The KS domain holds the growing fatty acid chain, whereas the ACP delivers two carbon fragments. 
C)  The KS domain associates with the fatty acid synthase enzyme, whereas the ACP does not. 
D)  The ACP delivers two carbon fragments one at a time, whereas the KS domain passes them on to the fatty acid. 
A)  The ACP carries the growing fatty acid chain more than the KS domain. 
B)  The KS domain holds the growing fatty acid chain, whereas the ACP delivers two carbon fragments. 
C)  The KS domain associates with the fatty acid synthase enzyme, whereas the ACP does not. 
D)  The ACP delivers two carbon fragments one at a time, whereas the KS domain passes them on to the fatty acid.

Question 15

Which group is responsible for activating phosphatidic acid for the synthesis of phospholipids?

Accepted Answer

A)  CoA 
B)  ATP 
C)  CO2 
D)  CTP 
A)  CoA 
B)  ATP 
C)  CO2 
D)  CTP

Question 16

Which enzyme catalyzes the modification of a fatty acid, so that it can be transported into the mitochondria for oxidation?

Accepted Answer

A)  acyl-CoA dehydrogenase 
B)  acetyl-CoA carboxylase 
C)  fatty acyl-CoA synthetase 
D)  carnitine acyltransferase I 
A)  acyl-CoA dehydrogenase 
B)  acetyl-CoA carboxylase 
C)  fatty acyl-CoA synthetase 
D)  carnitine acyltransferase I

Question 17

What enzyme catalyzes the following reaction in the first step of fatty acid synthesis?

Accepted Answer

A)  fatty acyl-CoA synthetase 
B)  acetyl-CoA carboxylase 
C)  fatty acid synthase 
D)  fatty acyl-CoA dehydrogenase 
A)  fatty acyl-CoA synthetase 
B)  acetyl-CoA carboxylase 
C)  fatty acid synthase 
D)  fatty acyl-CoA dehydrogenase

Question 18

Fill in the missing names or structures in the following triacylglycerol synthesis scheme.

Accepted Answer

The answer of Fill in the missing names or structures...

Question 19

Start with the following molecule. (A) Write the balanced equation for the products formed from its complete oxidation in the $\beta$-oxidation pathway and (B) show how many ATPs would
be obtained from the complete metabolism of those products.

Accepted Answer

The answer of Start with the following molecule. (A) Write...

Question 20

How many more enzymes does the oxidation of a polyunsaturated fat such as linoleoyl-CoA (18:2) require than the oxidation of stearoyl-CoA (18:0)?

Accepted Answer

A)  0 
B)  1 
C)  2 
D)  3 
A)  0 
B)  1 
C)  2 
D)  3

Exam 16: Lipid Metabolism

List in order the three most abundant molecule types found in an HDL.

Which enzyme activates acetyl-CoA so that it can be added to the growing fatty acid chain during the synthesis of palmitate?

The rate-limiting step of cholesterol synthesis involves controlling the fate of HMG-CoA. What other pathways is HMG-CoA involved in?

Explain how humans can create oleoyl-CoA (18:1 Δ\DeltaΔ 9) from stearoyl-CoA (18:0).

What are the known components of atherosclerotic plaques?

Starting from the 6C fatty acyl-CoA molecule shown below, draw the reactants and products, including all cofactors used for one round of the β\betaβ -oxidation pathway and list the enzyme types involved in each step.

Which of the following do β\betaβ -oxidation and fatty acid synthesis have in common?

List the four key steps in the synthesis of cholesterol.

List the primary three physiological roles played by cholesterol or cholesterol derivatives.

The β\betaβ -oxidation of mono- and polyunsaturated fatty acids

Which fatty acid can be synthesized from scratch in humans by desaturase enzymes?

LDLs are referred to as "bad cholesterol" because

Which enzyme catalyzes the rate-limiting step of cholesterol synthesis?

What are the different roles played the acyl carrier protein (ACP) and the ketoacyl synthase (KS) domain during fatty acid synthesis?

Which group is responsible for activating phosphatidic acid for the synthesis of phospholipids?

Which enzyme catalyzes the modification of a fatty acid, so that it can be transported into the mitochondria for oxidation?

What enzyme catalyzes the following reaction in the first step of fatty acid synthesis?

Fill in the missing names or structures in the following triacylglycerol synthesis scheme.

Start with the following molecule. (A) Write the balanced equation for the products formed from its complete oxidation in the β\betaβ -oxidation pathway and (B) show how many ATPs would be obtained from the complete metabolism of those products.

How many more enzymes does the oxidation of a polyunsaturated fat such as linoleoyl-CoA (18:2) require than the oxidation of stearoyl-CoA (18:0)?

Principles of Biochemistry

Physical Biochemistry: Energy Conversion, Water, and Membranes

Nucleic Acid Structure and Function

Protein Structure

Methods in Protein Biochemistry

Protein Function

Enzyme Mechanisms

Cell Signaling Systems

Glycolysis: a Paradigm of Metabolic Regulation

The Citrate Cycle

Oxidative Phosphorylation

Photosynthesis

Carbohydrate Structure and Function

Carbohydrate Metabolism

Lipid Structure and Function

Amino Acid Metabolism

Nucleotide Metabolism

Metabolic Integration

DNA Replication, Repair, and Recombination

RNA Synthesis, Processing, and Gene Silencing

Protein Synthesis, Posttranslational Modification, and Transport

Gene Regulation

Filters

Explain how humans can create oleoyl-CoA (18:1 $\Delta$ ⁹) from stearoyl-CoA (18:0).

Which of the following do $\beta$ -oxidation and fatty acid synthesis have in common?

The $\beta$ -oxidation of mono- and polyunsaturated fatty acids