Question 1

What type of linkage occurs between ACP and the intermediates in fatty acid biosynthesis?

Accepted Answer

A)  an ester 
B)  a thioester 
C)  an amide 
D)  an ether 
E)  an acetal 
A)  an ester 
B)  a thioester 
C)  an amide 
D)  an ether 
E)  an acetal

Question 2

Which of the following is FALSE regarding HDL pariticales?

Accepted Answer

A)  high HDL levels correlates with high risk of cardiovascular disease. 
B)  an HDL life span is typically 5 to 6 days. 
C)  they are initially formed as HDL precursors that contains no cholesterol or cholesterol esters. 
D)  scavenges excess cholesterol from extrahepatic tissue and returns cholesterol and cholesterol esters to liver. 
E)  accumulates cholesterol esters via LCAT action. 
A)  high HDL levels correlates with high risk of cardiovascular disease. 
B)  an HDL life span is typically 5 to 6 days. 
C)  they are initially formed as HDL precursors that contains no cholesterol or cholesterol esters. 
D)  scavenges excess cholesterol from extrahepatic tissue and returns cholesterol and cholesterol esters to liver. 
E)  accumulates cholesterol esters via LCAT action.

Question 3

What are low-density lipoproteins (LDLs)? How are they degraded in cells?​

Accepted Answer

LDL (low-density lipoprotein) appears to

Question 4

Which of the following is true regarding fatty acid elongation?

Accepted Answer

A)  malonyl CoA provides 2 carbons for each round of elongation 
B)  two reductions take place with both reactions using NADPH as the source of electrons 
C)  the fatty acid that is being elongated is attached to CoA 
D)  occurs only in cytosol 
E)  by not performing the second reduction reaction, an unsaturated fatty acid with a cis double bond can be formed 
A)  malonyl CoA provides 2 carbons for each round of elongation 
B)  two reductions take place with both reactions using NADPH as the source of electrons 
C)  the fatty acid that is being elongated is attached to CoA 
D)  occurs only in cytosol 
E)  by not performing the second reduction reaction, an unsaturated fatty acid with a cis double bond can be formed

Question 5

In eukaryotes, phosphatidic acid is converted directly either to ____ or to ____ from which all other ____ are derived.

Accepted Answer

A)  triacylglycerols; monoacylglycerols; acylglycerols 
B)  acylglycerols; phospholipids; glycerophospholipids 
C)  monoacylglycerols; phospholipids; glycerophospholipids 
D)  diacylglycerols; CDP-diacylglycerols; glycerophospholipids 
E)  diacylglycerols; CDP-diacylglycerols; acylglycerols 
A)  triacylglycerols; monoacylglycerols; acylglycerols 
B)  acylglycerols; phospholipids; glycerophospholipids 
C)  monoacylglycerols; phospholipids; glycerophospholipids 
D)  diacylglycerols; CDP-diacylglycerols; glycerophospholipids 
E)  diacylglycerols; CDP-diacylglycerols; acylglycerols

Question 6

The carbons of sphinganine are derived from:

Accepted Answer

A)  palmitate and glycerol. 
B)  arachidonate and glycine. 
C)  fatty alcohol and dihydroxyacetone phosphate (DHAP). 
D)  palmitate and serine. 
E)  none of the above. 
A)  palmitate and glycerol. 
B)  arachidonate and glycine. 
C)  fatty alcohol and dihydroxyacetone phosphate (DHAP). 
D)  palmitate and serine. 
E)  none of the above.

Question 7

The PRIMARY site, but not the only site, of cholesterol synthesis is:

Accepted Answer

A)  heart. 
B)  intestine. 
C)  muscle. 
D)  liver. 
E)  adipose. 
A)  heart. 
B)  intestine. 
C)  muscle. 
D)  liver. 
E)  adipose.

Question 8

CDP-diacylglycerols are precursors for the synthesis of all EXCEPT:

Accepted Answer

A)  phosphatidylethanolamine. 
B)  phosphatidyl glycerol. 
C)  cardiolipins. 
D)  phosphatidylinositol. 
E)  all are true. 
A)  phosphatidylethanolamine. 
B)  phosphatidyl glycerol. 
C)  cardiolipins. 
D)  phosphatidylinositol. 
E)  all are true.

Question 9

Both glycerol and dihydroxyacetone phosphate can serve as precursors for phosphatidic acid. Which enzyme is NOT USED to catalyze reactions in the synthesis of phosphatidic acid from these two precursors?

Accepted Answer

A)  glycerol kinase 
B)  triose phosphate isomerase 
C)  acyldihydroxyacetone-P reductase 
D)  glycerol-3-phosphate acyltransferase 
E)  1-acylglycerol-3-phosphate acyltransferase 
A)  glycerol kinase 
B)  triose phosphate isomerase 
C)  acyldihydroxyacetone-P reductase 
D)  glycerol-3-phosphate acyltransferase 
E)  1-acylglycerol-3-phosphate acyltransferase

Question 10

All are characteristics of COX-2 inhibitors EXCEPT:

Accepted Answer

A)  selectively block inflammation mediated by COX-2. 
B)  are NSAIDs. 
C)  less potential for stomach lesions than aspirin. 
D)  less renal toxicity than COX-1 inhibitors. 
E)  all are correct. 
A)  selectively block inflammation mediated by COX-2. 
B)  are NSAIDs. 
C)  less potential for stomach lesions than aspirin. 
D)  less renal toxicity than COX-1 inhibitors. 
E)  all are correct.

Question 11

Which of the following is correctly paired with its effect upon fatty acid synthesis?

Accepted Answer

A)  palmitoyl CoA: activates 
B)  glucagon: activates 
C)  insulin: inhibits 
D)  citrate: activates 
E)  NADPH: inhibits 
A)  palmitoyl CoA: activates 
B)  glucagon: activates 
C)  insulin: inhibits 
D)  citrate: activates 
E)  NADPH: inhibits

Question 12

Which of the following statements concerning eicosanoids is correct?

Accepted Answer

A)  all thromboxanes contain a 1,3-dioxane ring 
B)  all prostaglandins contain a cyclic ether 
C)  all leukotrienes contain three conjugated double bonds 
D)  leukotirenes are derived from prostaglandin H2 while thromboxanes are derived from arachidonic acid 
E)  none of the above 
A)  all thromboxanes contain a 1,3-dioxane ring 
B)  all prostaglandins contain a cyclic ether 
C)  all leukotrienes contain three conjugated double bonds 
D)  leukotirenes are derived from prostaglandin H2 while thromboxanes are derived from arachidonic acid 
E)  none of the above

Question 13

A lipid that does NOT have a sphingosine backbone is:

Accepted Answer

A)  ganglioside GM1. 
B)  sphingomyelin. 
C)  phosphatidylinositol. 
D)  ceramide. 
E)  cerebroside. 
A)  ganglioside GM1. 
B)  sphingomyelin. 
C)  phosphatidylinositol. 
D)  ceramide. 
E)  cerebroside.

Question 14

Lipoprotein lipase hydrolyzes ____ from VLDL particles to convert the VLDL into ____.

Accepted Answer

A)  cholesterol esters; HDL particles 
B)  cholesterol esters; LDL particles 
C)  triacylglycerols; LDL particles 
D)  triacylglycerols; chylomicrons 
E)  triacylglycerols; HDL particles 
A)  cholesterol esters; HDL particles 
B)  cholesterol esters; LDL particles 
C)  triacylglycerols; LDL particles 
D)  triacylglycerols; chylomicrons 
E)  triacylglycerols; HDL particles

Question 15

Order the lipoproteins from lowest density to highest density.
A.chylomicrons
B.HDL
C.IDL
D.VLDL
E.LDL

Accepted Answer

A)  D, A, E, B, C 
B)  D, E, C, B, A 
C)  A, E, B, D, C 
D)  D, C, A, E, B 
E)  A, D, C, E, B 
A)  D, A, E, B, C 
B)  D, E, C, B, A 
C)  A, E, B, D, C 
D)  D, C, A, E, B 
E)  A, D, C, E, B

Question 16

The role of citrate in fatty acid synthesis makes it an important regulator of the process. Which of the following enzymes would be allosterically activated by citrate?

Accepted Answer

A)  Citrate lyase 
B)  Malic enzyme 
C)  Acetyl-CoA carboxylase 
D)  β-ketoacyl-ACP synthase 
E)  None of the above 
A)  Citrate lyase 
B)  Malic enzyme 
C)  Acetyl-CoA carboxylase 
D)  β-ketoacyl-ACP synthase 
E)  None of the above

Question 17

HMG-CoA reductase, the regulatory enzyme for the synthesis of cholesterol, is inhibited by simvastatin. Based upon the structure of the product, mevalonate, and the structure of simvastatin, what sort of enzyme inhibition would be produced by simvastatin?

Accepted Answer

A)  competitive 
B)  non-competitive 
C)  uncompetitive 
D)  mechanism-based inactivator 
E)  none of the above 
A)  competitive 
B)  non-competitive 
C)  uncompetitive 
D)  mechanism-based inactivator 
E)  none of the above

Question 18

The "statins" are a series of drugs used to:

Accepted Answer

A)  inhibit fatty acid synthesis in diet drugs. 
B)  widely prescribed drugs used to inhibit squalene monooxygenase. 
C)  derivatives or mimics of mevinolin used to inhibit HMG-CoA reductase. 
D)  derivatives of cholesterol used to lower cholesterol levels. 
E)  none are true. 
A)  inhibit fatty acid synthesis in diet drugs. 
B)  widely prescribed drugs used to inhibit squalene monooxygenase. 
C)  derivatives or mimics of mevinolin used to inhibit HMG-CoA reductase. 
D)  derivatives of cholesterol used to lower cholesterol levels. 
E)  none are true.

Question 19

Characteristics of mixed-function oxidases include all EXCEPT:

Accepted Answer

A)  usually involve cytochrome P-450. 
B)  often catalyze hydroxylation reactions on ring-systems such as sterols. 
C)  use both NADPH and O2. 
D)  one product is CO2. 
E)  all are correct. 
A)  usually involve cytochrome P-450. 
B)  often catalyze hydroxylation reactions on ring-systems such as sterols. 
C)  use both NADPH and O2. 
D)  one product is CO2. 
E)  all are correct.

Question 20

The major circulatory complex for cholesterol and cholesterol esters that is often referred to a "bad cholesterol" is the:

Accepted Answer

A)  chylomicrons. 
B)  HDL. 
C)  IDL. 
D)  VLDL. 
E)  LDL. 
A)  chylomicrons. 
B)  HDL. 
C)  IDL. 
D)  VLDL. 
E)  LDL.

Exam 24: Lipid Biosynthesis

What type of linkage occurs between ACP and the intermediates in fatty acid biosynthesis?

Which of the following is FALSE regarding HDL pariticales?

What are low-density lipoproteins (LDLs)? How are they degraded in cells?​

Which of the following is true regarding fatty acid elongation?

In eukaryotes, phosphatidic acid is converted directly either to ____ or to ____ from which all other ____ are derived.

The carbons of sphinganine are derived from:

The PRIMARY site, but not the only site, of cholesterol synthesis is:

CDP-diacylglycerols are precursors for the synthesis of all EXCEPT:

Both glycerol and dihydroxyacetone phosphate can serve as precursors for phosphatidic acid. Which enzyme is NOT USED to catalyze reactions in the synthesis of phosphatidic acid from these two precursors?

All are characteristics of COX-2 inhibitors EXCEPT:

Which of the following is correctly paired with its effect upon fatty acid synthesis?

Which of the following statements concerning eicosanoids is correct?

A lipid that does NOT have a sphingosine backbone is:

Lipoprotein lipase hydrolyzes ____ from VLDL particles to convert the VLDL into ____.

Order the lipoproteins from lowest density to highest density. A.chylomicrons B.HDL C.IDL D.VLDL E.LDL

The role of citrate in fatty acid synthesis makes it an important regulator of the process. Which of the following enzymes would be allosterically activated by citrate?

HMG-CoA reductase, the regulatory enzyme for the synthesis of cholesterol, is inhibited by simvastatin. Based upon the structure of the product, mevalonate, and the structure of simvastatin, what sort of enzyme inhibition would be produced by simvastatin?

The "statins" are a series of drugs used to:

Characteristics of mixed-function oxidases include all EXCEPT:

The major circulatory complex for cholesterol and cholesterol esters that is often referred to a "bad cholesterol" is the:

The Facts of Life: Chemistry Is the Logic of Biological Phenomena

Water: the Medium of Life

Thermodynamics of Biological Systems

Amino Acids and the Peptide Bond

Proteins: Their Primary Structure and Biological Functions

Proteins: Secondary, Tertiary, and Quaternary Structure

Carbohydrates and the Glycoconjugates of Cell Surfaces

Lipids

Membranes and Membrane Transport

Nucleotides and Nucleic Acids

Structure of Nucleic Acids

Recombinant Dna, Cloning, Chimeric Genes, and Synthetic Biology

Enzymeskinetics and Specificity

Mechanisms of Enzyme Action

Enzyme Regulation

Molecular Motors

Metabolism: an Overview

Glycolysis

The Tricarboxylic Acid Cycle

Electron Transport and Oxidative Phosphorylation

Photosynthesis

Gluconeogenesis, Glycogen Metabolism, and the Pentose Phosphate Pathway

Fatty Acid Catabolism

Nitrogen Acquisition and Amino Acid Metabolism

Synthesis and Degradation of Nucleotides

Metabolic Integration and Organ Specialization

Dna Metabolism: Replication, Recombination, and Repair

Transcription and the Regulation of Gene Expression

Protein Synthesis

Completing the Protein Life Cycle: Folding, Processing, and Degradation

The Reception and Transmission of Extracellular Information

Filters

What are low-density lipoproteins (LDLs)? How are they degraded in cells?

In eukaryotes, phosphatidic acid is converted directly either to or to from which all other are derived.

Lipoprotein lipase hydrolyzes from VLDL particles to convert the VLDL into .