Question 1

Synthesis of cardiolipin from phosphatidate, CTP, and glycerol-3-phosphate in E. coli consumes how many phosphoanhydride bonds?

Accepted Answer

A)  zero 
B)  one 
C)  two 
D)  three 
E)  four

Question 2

Sketch the pathway from arachidonate to thromboxanes and explain how aspirin blocks the synthesis of thromboxanes.

Accepted Answer

The answer of Sketch the pathway from arachidonate to thromboxanes...

Question 3

Which statement is NOT true of the reaction producing malonyl-CoA during fatty acid synthesis?

Accepted Answer

A)  It is stimulated by citrate. 
B)  It requires acyl carrier protein (ACP). 
C)  It requires CO2 (or bicarbonate). 
D)  One mole of ATP is converted to ADP + Pi for each malonyl-CoA synthesized. 
E)  The cofactor is biotin.

Question 4

The synthesis of cholesterol begins with the condensation of a four-carbon unit from _____ with the two carbons of acetyl-CoA to form a six-carbon derivative. Give its structure, and circle the atoms that originated in the acetyl-CoA.

Accepted Answer

The answer of The synthesis of cholesterol begins with the...

Question 5

Show the structure of each intermediate in the conversion of $\beta$-hydroxybutyryl-ACP to butyryl-ACP by the fatty acid synthetase complex. Show where cofactors participate. In your first intermediate, circle the carbon atoms that are derived from malonyl-CoA.

Accepted Answer

The answer of Show the structure of each intermediate in...

Question 6

After four rounds of fatty acid synthase activity, what size is the fatty acyl intermediate?

Accepted Answer

A)  4 carbons long 
B)  5 carbons long 
C)  8 carbons long 
D)  9 carbons long 
E)  10 carbons long

Question 7

Which statement is NOT a step in the uptake of cholesterol from the bloodstream into cells?

Accepted Answer

A)  LDL containing ApoB-100 is recognized by the LDL receptor. 
B)  LDL bound to the LDL receptor leads to endocytosis of the complex. 
C)  The cholesteryl esters in the LDL are hydrolyzed to release free cholesterol. 
D)  The internalized receptor is degraded. 
E)  The ApoB-100 protein is degraded.

Question 8

Which statement does NOT describe a difference between fatty acid synthase I (FAS I) and fatty acid synthase II (FAS II)?

Accepted Answer

A)  FAS I is found in fungi, while FAS II is found in plants. 
B)  FAS I has no quaternary structure, while FAS II does. 
C)  Intermediates are not released in FAS I catalysis but are released in FAS II catalysis. 
D)  A single lipid product is produced from FAS I while multiple products may be produced by FAS II. 
E)  All of these statements describe differences between FAS I and FAS II.

Question 9

Which statement is NOT true about precursors required for fatty acid synthesis in animal cells?

Accepted Answer

A)  NADPH is produced in the cytosol by the pentose phosphate pathway. 
B)  NADPH is produced in the nucleus by malic enzyme. 
C)  Acetyl-CoA is transported out of the mitochondrion via the citrate shuttle. 
D)  CoA is not transported across the mitochondrial membrane. 
E)  Malonyl-CoA is formed in the cytosol.

Question 10

Which statement about the regulation of cholesterol synthesis is NOT true?

Accepted Answer

A)  Cholesterol acquired in the diet has essentially no effect on the synthesis of cholesterol in the liver. 
B)  Failure to regulate cholesterol synthesis predisposes humans to atherosclerosis. 
C)  High intracellular cholesterol stimulates formation of cholesteryl esters. 
D)  Insulin stimulates HMG-CoA reductase. 
E)  Some metabolite or derivative of cholesterol inhibits HMG-CoA reductase.

Question 11

Lipoprotein particles in human blood do NOT contain:

Accepted Answer

A)  an apolipoprotein B isoform. 
B)  cholesterol. 
C)  cholesteryl esters. 
D)  lecithin. 
E)  triglycerides.

Question 12

The rate-limiting step in fatty acid synthesis is:

Accepted Answer

A)  condensation of acetyl-CoA and malonyl-CoA. 
B)  formation of acetyl-CoA from acetate. 
C)  formation of malonyl-CoA from malonate and coenzyme A. 
D)  the reaction catalyzed by acetyl-CoA carboxylase. 
E)  the reduction of the acetoacetyl group to a $\beta$-hydroxybutyryl group.

Question 13

Which lipoproteins do NOT originate from the liver?

Accepted Answer

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

Question 14

Which statement applies to synthesis of fatty acids in E. coli extracts?

Accepted Answer

A)  Acyl intermediates are thioesters of a low molecular weight protein called acyl carrier protein. 
B)  CO2 or HCO3- is essential. 
C)  Reducing equivalents are provided by NADPH. 
D)  The ultimate source of all the carbon atoms in the fatty acid product is acetyl-CoA. 
E)  All of the statements apply to synthesis of fatty acids in E. coli extracts.

Question 15

Fatty acid synthesis and fatty acid breakdown occur by similar pathways. Describe, very briefly, four ways in which the synthetic and breakdown pathways differ.

Accepted Answer

The answer of Fatty acid synthesis and fatty acid breakdown...

Question 16

Which statement is FALSE regarding acyl-carrier protein (ACP)?

Accepted Answer

A)  ACP is transiently attached to malonyl-CoA during fatty acid elongation. 
B)  ACP contains a pantothenate-derived prosthetic group. 
C)  ACP carries reaction intermediates from one active site to the next in fatty acid synthesis. 
D)  ACP associates as a separate polypeptide with fatty acid synthase I in vertebrates. 
E)  Fatty acyl chains on ACP are transferred to a cysteine on $\beta$-ketoacyl-ACP synthase during fatty acid synthesis.

Question 17

Which statement is TRUE of sphingolipid synthesis?

Accepted Answer

A)  All of the carbon atoms of palmitate and serine are incorporated into sphingosine. 
B)  CDP-sphingosine is the activated intermediate. 
C)  CO2 is produced during the synthesis of ceramide from palmitate and serine. 
D)  Glucose 6-phosphate is the direct precursor of the glucose in cerebrosides. 
E)  Phosphatidic acid is a key intermediate in the pathway.

Question 18

Which list CORRECTLY ranks the polarity, from most polar to least polar, for the listed substances?

Accepted Answer

A)  cholesteryl-ester > bile salts > cholesterol 
B)  cholesterol > bile salts > cholesteryl-esters 
C)  bile salts > cholesteryl-esters > cholesterol 
D)  cholesteryl-esters > cholesterol > bile salts 
E)  bile salts > cholesterol > cholesteryl-esters

Question 19

Describe the process by which cholesterol esters in the bloodstream enter cells.

Accepted Answer

The answer of Describe the process by which cholesterol esters...

Question 20

In one cycle of acetyl transfer from mitochondria to the cytosol via citrate, what other net change occurs?

Accepted Answer

A)  net conversion of NADH to NADPH in the cytosol 
B)  net export of coenzyme A from mitochondria 
C)  net import of NADH from the cytosol into mitochondria 
D)  net consumption of 1 ATP 
E)  overall conversion of oxaloacetate into pyruvate

Exam 21: Lipid Biosynthesis

Synthesis of cardiolipin from phosphatidate, CTP, and glycerol-3-phosphate in E. coli consumes how many phosphoanhydride bonds?

Sketch the pathway from arachidonate to thromboxanes and explain how aspirin blocks the synthesis of thromboxanes.

Which statement is NOT true of the reaction producing malonyl-CoA during fatty acid synthesis?

The synthesis of cholesterol begins with the condensation of a four-carbon unit from _____ with the two carbons of acetyl-CoA to form a six-carbon derivative. Give its structure, and circle the atoms that originated in the acetyl-CoA.

Show the structure of each intermediate in the conversion of $\beta$ -hydroxybutyryl-ACP to butyryl-ACP by the fatty acid synthetase complex. Show where cofactors participate. In your first intermediate, circle the carbon atoms that are derived from malonyl-CoA.

After four rounds of fatty acid synthase activity, what size is the fatty acyl intermediate?

Which statement is NOT a step in the uptake of cholesterol from the bloodstream into cells?

Which statement does NOT describe a difference between fatty acid synthase I (FAS I) and fatty acid synthase II (FAS II) ?

Which statement is NOT true about precursors required for fatty acid synthesis in animal cells?

Which statement about the regulation of cholesterol synthesis is NOT true?

Lipoprotein particles in human blood do NOT contain:

The rate-limiting step in fatty acid synthesis is:

Which lipoproteins do NOT originate from the liver?

Which statement applies to synthesis of fatty acids in E. coli extracts?

Fatty acid synthesis and fatty acid breakdown occur by similar pathways. Describe, very briefly, four ways in which the synthetic and breakdown pathways differ.

Which statement is FALSE regarding acyl-carrier protein (ACP) ?

Which statement is TRUE of sphingolipid synthesis?

Which list CORRECTLY ranks the polarity, from most polar to least polar, for the listed substances?

Describe the process by which cholesterol esters in the bloodstream enter cells.

In one cycle of acetyl transfer from mitochondria to the cytosol via citrate, what other net change occurs?

Exam 21: Lipid Biosynthesis

Synthesis of cardiolipin from phosphatidate, CTP, and glycerol-3-phosphate in E. coli consumes how many phosphoanhydride bonds?

Sketch the pathway from arachidonate to thromboxanes and explain how aspirin blocks the synthesis of thromboxanes.

Which statement is NOT true of the reaction producing malonyl-CoA during fatty acid synthesis?

The synthesis of cholesterol begins with the condensation of a four-carbon unit from _____ with the two carbons of acetyl-CoA to form a six-carbon derivative. Give its structure, and circle the atoms that originated in the acetyl-CoA.

Show the structure of each intermediate in the conversion of β\betaβ -hydroxybutyryl-ACP to butyryl-ACP by the fatty acid synthetase complex. Show where cofactors participate. In your first intermediate, circle the carbon atoms that are derived from malonyl-CoA.

After four rounds of fatty acid synthase activity, what size is the fatty acyl intermediate?

Which statement is NOT a step in the uptake of cholesterol from the bloodstream into cells?

Which statement does NOT describe a difference between fatty acid synthase I (FAS I) and fatty acid synthase II (FAS II) ?

Which statement is NOT true about precursors required for fatty acid synthesis in animal cells?

Which statement about the regulation of cholesterol synthesis is NOT true?

Lipoprotein particles in human blood do NOT contain:

The rate-limiting step in fatty acid synthesis is:

Which lipoproteins do NOT originate from the liver?

Which statement applies to synthesis of fatty acids in E. coli extracts?

Fatty acid synthesis and fatty acid breakdown occur by similar pathways. Describe, very briefly, four ways in which the synthetic and breakdown pathways differ.

Which statement is FALSE regarding acyl-carrier protein (ACP) ?

Which statement is TRUE of sphingolipid synthesis?

Which list CORRECTLY ranks the polarity, from most polar to least polar, for the listed substances?

Describe the process by which cholesterol esters in the bloodstream enter cells.

In one cycle of acetyl transfer from mitochondria to the cytosol via citrate, what other net change occurs?

Show the structure of each intermediate in the conversion of $\beta$ -hydroxybutyryl-ACP to butyryl-ACP by the fatty acid synthetase complex. Show where cofactors participate. In your first intermediate, circle the carbon atoms that are derived from malonyl-CoA.