Question 1

The following fatty acid,in which the indicated carbon is labeled with 14C,is fed to an animal: 14CH3(CH2) 9COOH
After allowing 30 minutes for fatty acid  β\betaβ -oxidation,the label would most likely be recovered in:

Accepted Answer

A)  acetyl-CoA.
B)  beta-hydroxy butyryl-CoA.
C)  both acetyl-CoA and propionyl-CoA.
D)  palmitoyl-CoA.
E)  propionyl-CoA. F) B) and D)
G) A) and C)

Question 2

Which of the following statements apply (applies)  to the β-oxidation of fatty acids? 
1.  The process takes place in the cytosol of mammalian cells.
2.  Carbon atoms are removed from the acyl chain one at a time.
3.  Before oxidation, fatty acids must be converted to their CoA derivatives.
4.  NADP+ is the electron acceptor.
5.  The products of β-oxidation can directly enter the citric acid cycle for further oxidation.

Accepted Answer

A)  1 and 3 only
B)  1,2,and 3
C)  1,2,and 5
D)  3 and 5 only
E)  4 onlyF) A) and B)
G) B) and E)

Question 3

Describe the steps in the metabolic pathway in which cells oxidize a four-carbon,straight-chain,saturated fatty acid (butyrate;4:0)to the fragments that enter the citric acid cycle.Show the structures of intermediates and products,and indicate where any cofactor(s)participate(s).

Accepted Answer

Butyrate is first activated:
Butyrate + ...

Question 4

Explain the chemical reason why the addition of water across the double bond in the second step of $\beta$-oxidation occurs with the OH adding at the $\beta$-carbon,not the $\alpha$-carbon.Also,how does addition at the $\beta$-carbon aid in the subsequent step(s)of $\beta$-oxidation?

Accepted Answer

Recall that the carbon that is $\alpha$ to a carbonyl is readily able to become a carbanion;i.e.it is not a good electrophilic center for nucleophilic addition of a hydroxide (see Chapter 13).The $\beta$-carbon,by contrast is a good electrophilic center as can be readily shown by "pushing" the electrons from the C=C double bond onto the carbonyl oxygen.Addition of the OH in the $\beta$-position is useful for later steps since after oxidation of the OH to a carbonyl,the $\alpha$-carbon is even more susceptible to becoming a carbanion,as is needed for the reverse Claisen condensation catalyzed by thiolase.

Question 5

In the first step of fatty acid oxidation,the fatty acid (R-COOH)is converted to its coenzyme A derivative in the following reaction:
R-COOH + ATP + CoA-SH $\rightarrow$ R-CO-S-CoA + AMP + PPi
The standard free-energy change ($\Delta$G'° )for this reaction is -15 kJ/mol
What will tend to make the reaction even more favorable when it takes place within a cell?

Accepted Answer

The hydrolysis of PP_i

Question 6

The role of hormone-sensitive triacylglycerol lipase is to:

Accepted Answer

A)  hydrolyze lipids stored in the liver.
B)  hydrolyze membrane phospholipids in hormone-producing cells.
C)  hydrolyze triacylglycerols stored in adipose tissue.
D)  synthesize lipids in adipose tissue.
E)  synthesize triacylglycerols in the liver.F) B) and D)
G) C) and D)

Question 7

Which of the following is (are)  true of the oxidation of 1 mol of palmitate (a 16-carbon saturated fatty acid; 16:0)  by the β-oxidation pathway, beginning with the free fatty acid in the cytoplasm?
1. Activation of the free fatty acid requires the equivalent of two ATPs.
2. Inorganic pyrophosphate (PPi)  is produced.
3. Carnitine functions as an electron acceptor.
4. 8 mol of FADH2 are formed.
5. 8 mol of acetyl-CoA are formed.
6. There is no direct involvement of NAD+.

Accepted Answer

A)  1 and 5 only
B)  1,2,and 5
C)  1,2,and 6
D)  1,3,and 5
E)  5 onlyF) All of the above
G) A) and C)

Question 8

If an aerobic organism (e.g. ,the bacterium E.coli) were fed each of the following four compounds as a source of energy,the energy yield per mole from these molecules would be in the order:

Accepted Answer

A)  alanine > glucose > palmitate
B)  glucose > alanine > palmitate
C)  glucose > palmitate > alanine
D)  palmitate > alanine > glucose
E)  palmitate > glucose > alanineF) C) and D)
G) A) and E)

Question 9

In the disease sprue,vitamin B12 (cobalamin) is poorly absorbed in the intestine,resulting in B12 deficiency.If each of the following fatty acids were in the diet,for which one would the process of fatty acid oxidation be most affected in a patient with sprue?

Accepted Answer

A)  CH3(CH2) 10COOH
B)  CH3(CH2) 11COOH
C)  CH3(CH2) 12COOH
D)  CH3(CH2) 14COOH
E)  CH3(CH2) 18COOHF) A) and C)
G) C) and D)

Question 10

When comparing the  β\betaβ -oxidation and   ω \omega ω -oxidation pathways,which one of the following statements is correct?

Accepted Answer

A)  ( β\betaβ -oxidation and   ω \omega ω -oxidation occur in the cytoplasm.) 
B)  ( β\betaβ -oxidation occurs at the carboxyl end of the fatty acid whereas   ω \omega ω  oxidation occurs at the methyl end.) 
C)  ( β\betaβ -oxidation occurs at the methyl end of the fatty acid,whereas   ω \omega ω -oxidation occurs at the carboxyl end.) 
D)  ( β\betaβ -oxidation occurs mainly in the cytoplasm,whereas   ω \omega ω -oxidation occurs mainly in the mitochondria.) 
E)  ( β\betaβ -oxidation occurs mainly in the mitochondria,whereas   ω \omega ω -oxidation occurs mainly in the cytoplasm.)  F) B) and D)
G) A) and C)

Question 11

Draw the structure of one ketone body,and describe circumstances under which you would expect to find high concentrations of this compound in the urine of a human.

Accepted Answer

The ketone bodies,acetoacetate...

Question 12

The carbon atoms from a fatty acid with an odd number of carbons will enter the citric acid cycle as acetyl-CoA and:

Accepted Answer

A)  butyrate.
B)  citrate.
C)  malate.
D)  succinyl-CoA.
E)  ( α\alphaα -ketoglutarate.)  F) C) and D)
G) B) and E)

Question 13

Saturated fatty acids are degraded by the stepwise reactions of  β\betaβ -oxidation,producing acetyl-CoA.Under aerobic conditions,how many ATP molecules would be produced as a consequence of removal of each acetyl-CoA?

Accepted Answer

A)  2
B)  3
C)  4
D)  5
E)  6 F) C) and D)
G) B) and C)

Question 14

An experimenter studying the oxidation of fatty acids in extracts of liver found that when palmitate (16:0)was provided as substrate,it was completely oxidized to CO2.However,when undecanoic acid (11:0)was added as substrate,incomplete oxidation occurred unless he bubbled CO2 through the reaction mixture.The addition of the protein avidin,which binds tightly to biotin,prevented the complete oxidation of undecanoic acid even in the presence of CO2,although it had no effect on palmitate oxidation.Explain these observations in light of what you know of fatty acid oxidation reactions.

Accepted Answer

Oxidation of odd-chain fatty acid yields...

Question 15

Free fatty acids in the bloodstream are:

Accepted Answer

A)  bound to hemoglobin.
B)  carried by the protein serum albumin.
C)  freely soluble in the aqueous phase of the blood.
D)  nonexistent;the blood does not contain free fatty acids.
E)  present at levels that are independent of epinephrine.F) A) and B)
G) A) and C)

Question 16

The total degradation of a fatty acid with an odd number of carbons yields acetyl-CoA and another compound,X.Show the structure of X and describe the pathway by which it is converted into a citric acid cycle intermediate,including where any cofactors participate.

Accepted Answer

X is propionyl-CoA, and its conversion into succinyl-CoA is accomplished by the reactions in Fig. 17-12.

Question 17

Complete oxidation of 1 mole of which fatty acid would yield the most ATP?

Accepted Answer

A)  16-carbon saturated fatty acid
B)  18-carbon mono-unsaturated fatty acid
C)  16-carbon mono-unsaturated fatty acid
D)  16-carbon poly-unsaturated fatty acid
E)  14-carbon saturated fatty acidF) C) and E)
G) B) and E) B

Question 18

Which compound is an intermediate of the  β\betaβ -oxidation of fatty acids?

Accepted Answer

A)  CH3-(CH2) 20-CO-COOH
B)  CH3-CH2-CO-CH2-CO-OPO32- 
C)  CH3-CH2-CO-CH2-OH
D)  CH3-CH2-CO-CO-S-CoA
E)  CH3-CO-CH2-CO-S-CoA F) B) and E)
G) B) and D)

Question 19

Carnitine is:

Accepted Answer

A)  a 15-carbon fatty acid.
B)  an essential cofactor for the citric acid cycle.
C)  essential for intracellular transport of fatty acids.
D)  one of the amino acids commonly found in protein.
E)  present only in carnivorous animals.F) A) and E)
G) C) and D)

Question 20

Ketone bodies are formed in the liver and transported to the extrahepatic tissues mainly as:

Accepted Answer

A)  acetoacetyl-CoA.
B)  acetone.
C)  ( β\betaβ -hydroxybutyric acid.) 
D)  ( β\betaβ -hydroxybutyryl-CoA.) 
E)  lactic acid. F) A) and D)
G) A) and E)

Exam 17: Fatty Acid Catabolism

The following fatty acid,in which the indicated carbon is labeled with ¹⁴C,is fed to an animal: ¹⁴CH₃(CH₂) ₉COOH After allowing 30 minutes for fatty acid $\beta$ -oxidation,the label would most likely be recovered in:

Correct Answer
verified

Correct Answer
verified

Describe the steps in the metabolic pathway in which cells oxidize a four-carbon,straight-chain,saturated fatty acid (butyrate;4:0)to the fragments that enter the citric acid cycle.Show the structures of intermediates and products,and indicate where any cofactor(s)participate(s).

Correct Answer
verified
Butyrate is first activated:
Butyrate + ...
View Answer

Explain the chemical reason why the addition of water across the double bond in the second step of $\beta$ -oxidation occurs with the OH adding at the $\beta$ -carbon,not the $\alpha$ -carbon.Also,how does addition at the $\beta$ -carbon aid in the subsequent step(s)of $\beta$ -oxidation?

Correct Answer
verified
The hydrolysis of PP_{iView Answer}

The role of hormone-sensitive triacylglycerol lipase is to:

Correct Answer
verified

Correct Answer
verified

If an aerobic organism (e.g. ,the bacterium E.coli) were fed each of the following four compounds as a source of energy,the energy yield per mole from these molecules would be in the order:

Correct Answer
verified

In the disease sprue,vitamin B₁₂ (cobalamin) is poorly absorbed in the intestine,resulting in B₁₂ deficiency.If each of the following fatty acids were in the diet,for which one would the process of fatty acid oxidation be most affected in a patient with sprue?

Correct Answer
verified

When comparing the $\beta$ -oxidation and $\omega$ -oxidation pathways,which one of the following statements is correct?

Correct Answer
verified

Draw the structure of one ketone body,and describe circumstances under which you would expect to find high concentrations of this compound in the urine of a human.

Correct Answer
verified
The ketone bodies,acetoacetate...
View Answer

The carbon atoms from a fatty acid with an odd number of carbons will enter the citric acid cycle as acetyl-CoA and:

Correct Answer
verified

Saturated fatty acids are degraded by the stepwise reactions of $\beta$ -oxidation,producing acetyl-CoA.Under aerobic conditions,how many ATP molecules would be produced as a consequence of removal of each acetyl-CoA?

Correct Answer
verified

Correct Answer
verified
Oxidation of odd-chain fatty acid yields...
View Answer

Free fatty acids in the bloodstream are:

Correct Answer
verified

The total degradation of a fatty acid with an odd number of carbons yields acetyl-CoA and another compound,X.Show the structure of X and describe the pathway by which it is converted into a citric acid cycle intermediate,including where any cofactors participate.

Correct Answer
verified
X is propionyl-CoA, and its conversion into succinyl-CoA is accomplished by the reactions in Fig. 17-12.

Complete oxidation of 1 mole of which fatty acid would yield the most ATP?

Correct Answer
verified
B

Which compound is an intermediate of the $\beta$ -oxidation of fatty acids?

Correct Answer
verified

Carnitine is:

Correct Answer
verified

Ketone bodies are formed in the liver and transported to the extrahepatic tissues mainly as:

Correct Answer
verified

Exam 17: Fatty Acid Catabolism

The following fatty acid,in which the indicated carbon is labeled with 14C,is fed to an animal: 14CH3(CH2) 9COOH After allowing 30 minutes for fatty acid β\betaβ -oxidation,the label would most likely be recovered in:

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

Describe the steps in the metabolic pathway in which cells oxidize a four-carbon,straight-chain,saturated fatty acid (butyrate;4:0)to the fragments that enter the citric acid cycle.Show the structures of intermediates and products,and indicate where any cofactor(s)participate(s).

Correct AnswerverifiedButyrate is first activated:Butyrate + ...View AnswerShow Answer

Explain the chemical reason why the addition of water across the double bond in the second step of β\betaβ -oxidation occurs with the OH adding at the β\betaβ -carbon,not the α\alphaα -carbon.Also,how does addition at the β\betaβ -carbon aid in the subsequent step(s)of β\betaβ -oxidation?

Correct AnswerverifiedThe hydrolysis of PPiView AnswerShow Answer

The role of hormone-sensitive triacylglycerol lipase is to:

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

If an aerobic organism (e.g. ,the bacterium E.coli) were fed each of the following four compounds as a source of energy,the energy yield per mole from these molecules would be in the order:

Correct AnswerverifiedShow Answer

In the disease sprue,vitamin B12 (cobalamin) is poorly absorbed in the intestine,resulting in B12 deficiency.If each of the following fatty acids were in the diet,for which one would the process of fatty acid oxidation be most affected in a patient with sprue?

Correct AnswerverifiedShow Answer

When comparing the β\betaβ -oxidation and ω \omega ω -oxidation pathways,which one of the following statements is correct?

Correct AnswerverifiedShow Answer

Draw the structure of one ketone body,and describe circumstances under which you would expect to find high concentrations of this compound in the urine of a human.

Correct AnswerverifiedThe ketone bodies,acetoacetate...View AnswerShow Answer

The carbon atoms from a fatty acid with an odd number of carbons will enter the citric acid cycle as acetyl-CoA and:

Correct AnswerverifiedShow Answer

Saturated fatty acids are degraded by the stepwise reactions of β\betaβ -oxidation,producing acetyl-CoA.Under aerobic conditions,how many ATP molecules would be produced as a consequence of removal of each acetyl-CoA?

Correct AnswerverifiedShow Answer

Correct AnswerverifiedOxidation of odd-chain fatty acid yields...View AnswerShow Answer

Free fatty acids in the bloodstream are:

Correct AnswerverifiedShow Answer

The total degradation of a fatty acid with an odd number of carbons yields acetyl-CoA and another compound,X.Show the structure of X and describe the pathway by which it is converted into a citric acid cycle intermediate,including where any cofactors participate.

Correct AnswerverifiedX is propionyl-CoA, and its conversion into succinyl-CoA is accomplished by the reactions in Fig. 17-12.

Complete oxidation of 1 mole of which fatty acid would yield the most ATP?

Correct AnswerverifiedB

Which compound is an intermediate of the β\betaβ -oxidation of fatty acids?

Correct AnswerverifiedShow Answer

Carnitine is:

Correct AnswerverifiedShow Answer

Ketone bodies are formed in the liver and transported to the extrahepatic tissues mainly as:

Correct AnswerverifiedShow Answer

The following fatty acid,in which the indicated carbon is labeled with ¹⁴C,is fed to an animal: ¹⁴CH₃(CH₂) ₉COOH After allowing 30 minutes for fatty acid $\beta$ -oxidation,the label would most likely be recovered in:

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified
Butyrate is first activated:
Butyrate + ...
View Answer

Explain the chemical reason why the addition of water across the double bond in the second step of $\beta$ -oxidation occurs with the OH adding at the $\beta$ -carbon,not the $\alpha$ -carbon.Also,how does addition at the $\beta$ -carbon aid in the subsequent step(s)of $\beta$ -oxidation?

Correct Answer
verified
The hydrolysis of PP_{iView Answer}

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

In the disease sprue,vitamin B₁₂ (cobalamin) is poorly absorbed in the intestine,resulting in B₁₂ deficiency.If each of the following fatty acids were in the diet,for which one would the process of fatty acid oxidation be most affected in a patient with sprue?

Correct Answer
verified

When comparing the $\beta$ -oxidation and $\omega$ -oxidation pathways,which one of the following statements is correct?

Correct Answer
verified

Correct Answer
verified
The ketone bodies,acetoacetate...
View Answer

Correct Answer
verified

Saturated fatty acids are degraded by the stepwise reactions of $\beta$ -oxidation,producing acetyl-CoA.Under aerobic conditions,how many ATP molecules would be produced as a consequence of removal of each acetyl-CoA?

Correct Answer
verified

Correct Answer
verified
Oxidation of odd-chain fatty acid yields...
View Answer

Correct Answer
verified

Correct Answer
verified
X is propionyl-CoA, and its conversion into succinyl-CoA is accomplished by the reactions in Fig. 17-12.

Correct Answer
verified
B

Which compound is an intermediate of the $\beta$ -oxidation of fatty acids?

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified