Question 1

What enzyme class catalyzes the following reaction? (Note that there may be some missing reactants and products.)

Accepted Answer

A)  lyase 
B)  hydrolase 
C)  transferase 
D)  dehydrogenase 
A)  lyase 
B)  hydrolase 
C)  transferase 
D)  dehydrogenase

Question 2

A difference between FA synthesis and $\beta$-oxidation is that FA synthesis , whereas $\beta$-oxidation _.

Accepted Answer

A)  reactions use ATP; reactions directly yield ATP 
B)  occurs in the mitochondria; takes place in the cytoplasm 
C)  uses NADH; uses NADPH 
D)  uses acyl-ACP; uses acyl-CoA 
A)  reactions use ATP; reactions directly yield ATP 
B)  occurs in the mitochondria; takes place in the cytoplasm 
C)  uses NADH; uses NADPH 
D)  uses acyl-ACP; uses acyl-CoA

Question 3

Draw the overall balanced reaction for the breakdown of palmitic acid (16:0) to give all acetyl-CoA products. Please include all cofactors involved in the process.

Accepted Answer

palmitate + 7 NAD⁺+ 7

Question 4

Which correctly describes the synthesis of phosphatidylethanolamine?

Accepted Answer

A)  Activated ethanolamine is added to a phosphatidic acid precursor. 
B)  Phosphatidylserine is decarboxylated. 
C)  Diacylglycerol is activated by CTP. 
D)  Triacylglycerol is phosphorylated with ATP. 
A)  Activated ethanolamine is added to a phosphatidic acid precursor. 
B)  Phosphatidylserine is decarboxylated. 
C)  Diacylglycerol is activated by CTP. 
D)  Triacylglycerol is phosphorylated with ATP.

Question 5

Describe the role that AMP-activated protein kinase (AMPK) plays in the regulation of fatty acid synthesis.

Accepted Answer

AMPK is activated by phosphorylation as

Question 6

How many acetyl-CoAs per ketone body are delivered to cells in need of energy?

Accepted Answer

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

Question 7

Which lipid is thought to give rise to the plaques that can clog arteries?

Accepted Answer

A)  HDL 
B)  LDL 
C)  VLDL 
D)  chylomicrons 
A)  HDL 
B)  LDL 
C)  VLDL 
D)  chylomicrons

Question 8

Draw and name the two products obtained from the last round of $\beta$-oxidation of an odd-chain fatty acid.

Accepted Answer

Acetyl-CoA

Question 9

Why is the fatty acid oxidation pathway also referred to as the $\beta$-oxidation pathway?

Accepted Answer

A)  The carbon adjacent to the fatty acyl-CoA reacts with oxygen. 
B)  The pathway utilizes NAD+ and FAD as cofactors. 
C)  A carbon atom that is two carbons away from the carboxylic acid end of the fatty acid chain is oxidized. 
D)  The resulting products are referred to as $\beta$-bodies. 
A)  The carbon adjacent to the fatty acyl-CoA reacts with oxygen. 
B)  The pathway utilizes NAD+ and FAD as cofactors. 
C)  A carbon atom that is two carbons away from the carboxylic acid end of the fatty acid chain is oxidized. 
D)  The resulting products are referred to as $\beta$-bodies.

Question 10

What is the primary difference in the oxidation of stearic acid (18:0) and oleic acid (18:1)?

Accepted Answer

A)  Stearic acid requires one more pass through the fatty acid oxidation pathway. 
B)  Oleic acid will yield one less FADH2 product molecule. 
C)  Oleic acid cannot be fully metabolized. 
D)  Stearic acid yields less ATP. 
A)  Stearic acid requires one more pass through the fatty acid oxidation pathway. 
B)  Oleic acid will yield one less FADH2 product molecule. 
C)  Oleic acid cannot be fully metabolized. 
D)  Stearic acid yields less ATP.

Question 11

How many passes through the fatty acid oxidation pathway are required to degrade palmitic acid?

Accepted Answer

A)  1 
B)  7 
C)  8 
D)  16 
A)  1 
B)  7 
C)  8 
D)  16

Question 12

By what process are LDL particles removed selectively from the blood serum?

Accepted Answer

A)  through targeted digestion by serum lipases 
B)  by receptor-mediated endocytosis 
C)  They are replenished with triacylglycerols and never removed. 
D)  They form atherosclerotic plaques. 
A)  through targeted digestion by serum lipases 
B)  by receptor-mediated endocytosis 
C)  They are replenished with triacylglycerols and never removed. 
D)  They form atherosclerotic plaques.

Question 13

Identify the name of the group shown below that is common to CoA and the acyl carrier protein.

Accepted Answer

Phosphopan

Question 14

What class of enzyme is the human desaturase enzyme?

Accepted Answer

A)  isomerase 
B)  oxidoreductase 
C)  ATPase 
D)  transferase 
A)  isomerase 
B)  oxidoreductase 
C)  ATPase 
D)  transferase

Question 15

Membrane phospholipids are synthesized in which cellular location?

Accepted Answer

A)  cytoplasm 
B)  mitochondrial intermembrane space 
C)  mitochondrial matrix 
D)  smooth endoplasmic reticulum 
A)  cytoplasm 
B)  mitochondrial intermembrane space 
C)  mitochondrial matrix 
D)  smooth endoplasmic reticulum

Question 16

What is the key enzyme involved in priming fatty acids for degradation?

Accepted Answer

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

Question 17

How do we deal with the double bonds during the degradation of unsaturated fatty acids?

Accepted Answer

A)  Convert the three-carbon propionyl-CoA to succinyl-CoA and feed it into the TCA cycle. 
B)  Converge them with the TCA cycle to produce acetyl-CoAs. 
C)  Isomerize the position of the double bonds to converge them with the $\beta$-oxidation pathway. 
D)  Reduce them to single bonds and feed the saturated fatty acid into the $\beta$-oxidation pathway. 
A)  Convert the three-carbon propionyl-CoA to succinyl-CoA and feed it into the TCA cycle. 
B)  Converge them with the TCA cycle to produce acetyl-CoAs. 
C)  Isomerize the position of the double bonds to converge them with the $\beta$-oxidation pathway. 
D)  Reduce them to single bonds and feed the saturated fatty acid into the $\beta$-oxidation pathway.

Question 18

Why is less ATP obtained from the average carbon in a sugar molecule than from a carbon in a fat molecule?

Accepted Answer

A)  The sugar carbons require more water weight during cellular storage. 
B)  The carbons in fatty acids are a more reduced form of carbon than those in sugars. 
C)  The sugar carbons yield more NADH than ATP. 
D)  The sugar carbons are derived from CO2. 
A)  The sugar carbons require more water weight during cellular storage. 
B)  The carbons in fatty acids are a more reduced form of carbon than those in sugars. 
C)  The sugar carbons yield more NADH than ATP. 
D)  The sugar carbons are derived from CO2.

Question 19

The synthesis of palmitic acid

Accepted Answer

A)  occurs in mitochondria. 
B)  involves the acyl carrier protein (ACP). 
C)  uses FAD and NADP+. 
D)  requires ATP. 
A)  occurs in mitochondria. 
B)  involves the acyl carrier protein (ACP). 
C)  uses FAD and NADP+. 
D)  requires ATP.

Question 20

Draw the structure of malonyl-CoA, the activated form of acetyl-CoA for fatty acid synthesis.

Accepted Answer

The answer of Draw the structure of malonyl-CoA, the activated...

Exam 16: Lipid Metabolism

What enzyme class catalyzes the following reaction? (Note that there may be some missing reactants and products.)

A difference between FA synthesis and β\betaβ -oxidation is that FA synthesis , whereas β\betaβ -oxidation _.

Draw the overall balanced reaction for the breakdown of palmitic acid (16:0) to give all acetyl-CoA products. Please include all cofactors involved in the process.

Which correctly describes the synthesis of phosphatidylethanolamine?

Describe the role that AMP-activated protein kinase (AMPK) plays in the regulation of fatty acid synthesis.

How many acetyl-CoAs per ketone body are delivered to cells in need of energy?

Which lipid is thought to give rise to the plaques that can clog arteries?

Draw and name the two products obtained from the last round of β\betaβ -oxidation of an odd-chain fatty acid.

Why is the fatty acid oxidation pathway also referred to as the β\betaβ -oxidation pathway?

What is the primary difference in the oxidation of stearic acid (18:0) and oleic acid (18:1)?

How many passes through the fatty acid oxidation pathway are required to degrade palmitic acid?

By what process are LDL particles removed selectively from the blood serum?

Identify the name of the group shown below that is common to CoA and the acyl carrier protein.

What class of enzyme is the human desaturase enzyme?

Membrane phospholipids are synthesized in which cellular location?

What is the key enzyme involved in priming fatty acids for degradation?

How do we deal with the double bonds during the degradation of unsaturated fatty acids?

Why is less ATP obtained from the average carbon in a sugar molecule than from a carbon in a fat molecule?

The synthesis of palmitic acid

Draw the structure of malonyl-CoA, the activated form of acetyl-CoA for fatty acid synthesis.

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

A difference between FA synthesis and $\beta$ -oxidation is that FA synthesis , whereas $\beta$ -oxidation _.

Draw and name the two products obtained from the last round of $\beta$ -oxidation of an odd-chain fatty acid.

Why is the fatty acid oxidation pathway also referred to as the $\beta$ -oxidation pathway?