Question 1

Fatty acids are activated to acyl-CoAs and the acyl group is further transferred to carnitine because:

Accepted Answer

A) acyl-carnitines readily cross the mitochondrial inner membrane,but acyl-CoAs do not. 
B) acyl-CoAs easily cross the mitochondrial membrane,but the fatty acids themselves will not. 
C) carnitine is required to oxidize NAD+ to NADH. 
D) fatty acids cannot be oxidized by FAD unless they are in the acyl-carnitine form. 
E) None of the above is true. 
A) acyl-carnitines readily cross the mitochondrial inner membrane,but acyl-CoAs do not. 
B) acyl-CoAs easily cross the mitochondrial membrane,but the fatty acids themselves will not. 
C) carnitine is required to oxidize NAD+ to NADH. 
D) fatty acids cannot be oxidized by FAD unless they are in the acyl-carnitine form. 
E) None of the above is true.

Question 2

One of the steps in fatty acid oxidation in mitochondria involves the addition of water across a double bond.What is the next step in the process? Show structures and indicate where any cofactor(s)participate(s).

Accepted Answer

The reaction is that catalyzed

Question 3

Why is it more efficient to store energy as lipid rather than as glycogen?

Accepted Answer

First,the energy yield per gram of lipid

Question 4

Transport of fatty acids from the cytoplasm to the mitochondrial matrix requires:

Accepted Answer

A) ATP,carnitine,and coenzyme A. 
B) ATP,carnitine,and pyruvate dehydrogenase. 
C) ATP,coenzyme A,and hexokinase. 
D) ATP,coenzyme A,and pyruvate dehydrogenase. 
E) carnitine,coenzyme A,and hexokinase. 
A) ATP,carnitine,and coenzyme A. 
B) ATP,carnitine,and pyruvate dehydrogenase. 
C) ATP,coenzyme A,and hexokinase. 
D) ATP,coenzyme A,and pyruvate dehydrogenase. 
E) carnitine,coenzyme A,and hexokinase.

Question 5

Draw the first two steps of $\beta$-oxidation of saturated fatty acids.Show structures and indicate where any cofactors participate.

Accepted Answer

The reactions are those catalyzed by fat

Question 6

Two vitamins,biotin and vitamin B12,play crucial roles in the metabolism of propionic acid (propionate).Explain this by showing the steps in which each is essential in propionate metabolism.

Accepted Answer

Biotin and vitamin B₁₂ act as co

Question 7

The metabolite that regulates the activity of carnitine acyl transferase I is:

Accepted Answer

A) acetyl-CoA. 
B) carnitine-CoA. 
C) malonyl-CoA. 
D) NADH. 
E) CoA. 
A) acetyl-CoA. 
B) carnitine-CoA. 
C) malonyl-CoA. 
D) NADH. 
E) CoA.

Question 8

Which enzyme is the major regulatory control point for $\beta$-oxidation?

Accepted Answer

A) Pyruvate carboxylase 
B) Carnitine acyl transferase I 
C) Acetyl CoA dehydrogenase 
D) Enoyl CoA isomerase 
E) Methylmalonyl CoA mutase 
A) Pyruvate carboxylase 
B) Carnitine acyl transferase I 
C) Acetyl CoA dehydrogenase 
D) Enoyl CoA isomerase 
E) Methylmalonyl CoA mutase

Question 9

Write a balanced equation for the $\beta$-oxidation of palmitoyl-CoA,a 16-carbon,fully saturated fatty acid,and indicate how much of each product is formed.

Accepted Answer

The overall reaction is:
Palmi

Question 10

During $\beta$-oxidation of fatty acids,___________ is produced in peroxisomes but not in mitochondria.

Accepted Answer

A) acetyl-CoA 
B) FADH2  
C) H2O 
D) H2O2  
E) NADH 
A) acetyl-CoA 
B) FADH2  
C) H2O 
D) H2O2  
E) NADH

Question 11

Which of the following statements concerning the $\beta$-oxidation of fatty acids is true?

Accepted Answer

A) About 1200 ATP molecules are ultimately produced per 20-carbon fatty acid oxidized. 
B) One FADH2 and two NADH are produced for each acetyl-CoA. 
C) The free fatty acid must be carboxylated in the $\beta$ position by a biotin-dependent reaction before the process of $\beta$-oxidation commences. 
D) The free fatty acid must be converted to a thioester before the process of $\beta$-oxidation commences. 
E) Two NADH are produced for each acetyl-CoA. 
A) About 1200 ATP molecules are ultimately produced per 20-carbon fatty acid oxidized. 
B) One FADH2 and two NADH are produced for each acetyl-CoA. 
C) The free fatty acid must be carboxylated in the $\beta$ position by a biotin-dependent reaction before the process of $\beta$-oxidation commences. 
D) The free fatty acid must be converted to a thioester before the process of $\beta$-oxidation commences. 
E) Two NADH are produced for each acetyl-CoA.

Question 12

The major site of formation of acetoacetate from fatty acids is the:

Accepted Answer

A) adipose tissue. 
B) intestinal mucosa. 
C) kidney. 
D) liver. 
E) muscle. 
A) adipose tissue. 
B) intestinal mucosa. 
C) kidney. 
D) liver. 
E) muscle.

Question 13

The conversion of palmitoyl-CoA (16:0)to myristoyl-CoA (14:0)and 1 mol of acetyl-CoA by the $\beta$-oxidation pathway results in the net formation of:

Accepted Answer

A) 1 FADH2 and 1 NADH. 
B) 1 FADH2 and 1 NADPH. 
C) 1 FADH2,1 NADH,and 1 ATP. 
D) 2 FADH2 and 2 NADH. 
E) 2 FADH2,2 NADH,and 1 ATP. 
A) 1 FADH2 and 1 NADH. 
B) 1 FADH2 and 1 NADPH. 
C) 1 FADH2,1 NADH,and 1 ATP. 
D) 2 FADH2 and 2 NADH. 
E) 2 FADH2,2 NADH,and 1 ATP.

Question 14

For each two-carbon increase in the length of a saturated fatty acid chain,how many additional moles of ATP can be formed upon complete oxidation of one mole of the fatty acid to CO2 and H2O?

Accepted Answer

Each -CH₂-CH₂- uni

Question 15

Explain why lipases are required in both the intestine and in the bloodstream?

Accepted Answer

Fats ingested in the diet are mostly fou

Question 16

Which of the following is (are) true of the -oxidation of long-chain fatty acids?
1. The enzyme complex that catalyzes the reaction contains biotin.
2. FADH2 serves as an electron carrier.
3. NADH serves as an electron carrier.
4. Oxidation of an 18-carbon fatty acid produces six molecules of propionyl-CoA.
5. Oxidation of a 15-carbon fatty acid produces at least one propionyl-CoA.

Accepted Answer

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

Question 17

Describe the steps in the metabolic pathway in which cells oxidize a five-carbon,straight-chain,saturated fatty acid (valerate;5:0)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

Valerate is first activated:
valerate +

Question 18

What is the correct order of function of the following enzymes of -oxidation?
1. β-Hydroxyacyl-CoA dehydrogenase
2. Thiolase
3. Enoyl-CoA hydratase
4. Acyl-CoA dehydrogenase

Accepted Answer

A) 1,2,3,4 
B) 3,1,4,2 
C) 4,3,1,2 
D) 1,4,3,2 
E) 4,2,3,1 
A) 1,2,3,4 
B) 3,1,4,2 
C) 4,3,1,2 
D) 1,4,3,2 
E) 4,2,3,1

Question 19

Which of the following is not true regarding the oxidation of 1 mol of palmitate (16:0)by the $\beta$-oxidation pathway?

Accepted Answer

A) 1 mol of ATP is needed. 
B) 8 mol of acetyl-CoA are formed. 
C) 8 mol of FADH2 are formed. 
D) AMP and PPi are formed. 
E) The reactions occur in the mitochondria. 
A) 1 mol of ATP is needed. 
B) 8 mol of acetyl-CoA are formed. 
C) 8 mol of FADH2 are formed. 
D) AMP and PPi are formed. 
E) The reactions occur in the mitochondria.

Question 20

What are the two major differences between the $\beta$-oxidation pathway in mitochondria and the $\beta$-oxidation pathway in peroxisomes?

Accepted Answer

The first major difference lies in the d

Exam 17: Fatty Acid Catabolism

Fatty acids are activated to acyl-CoAs and the acyl group is further transferred to carnitine because:

One of the steps in fatty acid oxidation in mitochondria involves the addition of water across a double bond.What is the next step in the process? Show structures and indicate where any cofactor(s)participate(s).

Why is it more efficient to store energy as lipid rather than as glycogen?

Transport of fatty acids from the cytoplasm to the mitochondrial matrix requires:

Draw the first two steps of β\betaβ -oxidation of saturated fatty acids.Show structures and indicate where any cofactors participate.

Two vitamins,biotin and vitamin B12,play crucial roles in the metabolism of propionic acid (propionate).Explain this by showing the steps in which each is essential in propionate metabolism.

The metabolite that regulates the activity of carnitine acyl transferase I is:

Which enzyme is the major regulatory control point for β\betaβ -oxidation?

Write a balanced equation for the β\betaβ -oxidation of palmitoyl-CoA,a 16-carbon,fully saturated fatty acid,and indicate how much of each product is formed.

During β\betaβ -oxidation of fatty acids,___________ is produced in peroxisomes but not in mitochondria.

Which of the following statements concerning the β\betaβ -oxidation of fatty acids is true?

The major site of formation of acetoacetate from fatty acids is the:

The conversion of palmitoyl-CoA (16:0)to myristoyl-CoA (14:0)and 1 mol of acetyl-CoA by the β\betaβ -oxidation pathway results in the net formation of:

For each two-carbon increase in the length of a saturated fatty acid chain,how many additional moles of ATP can be formed upon complete oxidation of one mole of the fatty acid to CO2 and H2O?

Explain why lipases are required in both the intestine and in the bloodstream?

Describe the steps in the metabolic pathway in which cells oxidize a five-carbon,straight-chain,saturated fatty acid (valerate;5:0)to the fragments that enter the citric acid cycle.Show the structures of intermediates and products,and indicate where any cofactor(s)participate(s).

What is the correct order of function of the following enzymes of -oxidation? 1. β-Hydroxyacyl-CoA dehydrogenase 2. Thiolase 3. Enoyl-CoA hydratase 4. Acyl-CoA dehydrogenase

Which of the following is not true regarding the oxidation of 1 mol of palmitate (16:0)by the β\betaβ -oxidation pathway?

What are the two major differences between the β\betaβ -oxidation pathway in mitochondria and the β\betaβ -oxidation pathway in peroxisomes?

The Foundations of Biochemistry

Water

Amino Acids, peptides, and Proteins

The Three-Dimensional Structure of Proteins

Protein Function

Enzymes

Carbohydrates and Glycobiology

Nucleotides and Nucleic Acids

Recombinant Dna Technology

Lipids

Biological Membranes and Transport

Biosignaling

Principles of Bioenergetics

Glycolysis, gluconeogenesis, and the Pentose Phosphate Pathway

Principles of Metabolic Regulation

The Citric Acid Cycle

Amino Acid Oxidation and the Production of Urea

Oxidative Phosphorylation and Photophosphorylation

Carbohydrate Biosynthesis in Plants and Bacteria

Lipid Biosynthesis

Biosynthesis of Amino Acids, nucleotides, and Related Molecules

Integration and Hormonal Regulation of Mammalian Metabolism

Genes and Chromosomes

Dna Metabolism

Rna Metabolism

Protein Metabolism

Regulation of Gene Expression

Filters

Draw the first two steps of $\beta$ -oxidation of saturated fatty acids.Show structures and indicate where any cofactors participate.

Two vitamins,biotin and vitamin B₁₂,play crucial roles in the metabolism of propionic acid (propionate).Explain this by showing the steps in which each is essential in propionate metabolism.

Which enzyme is the major regulatory control point for $\beta$ -oxidation?

Write a balanced equation for the $\beta$ -oxidation of palmitoyl-CoA,a 16-carbon,fully saturated fatty acid,and indicate how much of each product is formed.

During $\beta$ -oxidation of fatty acids,___________ is produced in peroxisomes but not in mitochondria.

Which of the following statements concerning the $\beta$ -oxidation of fatty acids is true?

The conversion of palmitoyl-CoA (16:0)to myristoyl-CoA (14:0)and 1 mol of acetyl-CoA by the $\beta$ -oxidation pathway results in the net formation of:

For each two-carbon increase in the length of a saturated fatty acid chain,how many additional moles of ATP can be formed upon complete oxidation of one mole of the fatty acid to CO₂ and H₂O?

Which of the following is not true regarding the oxidation of 1 mol of palmitate (16:0)by the $\beta$ -oxidation pathway?

What are the two major differences between the $\beta$ -oxidation pathway in mitochondria and the $\beta$ -oxidation pathway in peroxisomes?