Question 1

The carbon skeletons used to synthesize amino acids are intermediates found in

Accepted Answer

A)  glycolysis. 
B)  glycogen metabolism. 
C)  citric acid cycle. 
D)  All the answers are correct. 
E)  glycolysis and citric acid cycle 
A)  glycolysis. 
B)  glycogen metabolism. 
C)  citric acid cycle. 
D)  All the answers are correct. 
E)  glycolysis and citric acid cycle E

Question 2

Essential amino acids (for humans)differ from nonessential amino acids in that

Accepted Answer

A)  nonessential amino acids are synthesized in simple reaction pathways compared to complex pathways for most essential amino acids. 
B)  essential amino acids are generally synthesized directly from citric acid cycle intermediates, but not nonessential amino acids. 
C)  microorganisms and animals cannot synthesize essential amino acids but plants can. 
D)  animals cannot synthesize essential amino acids because they have lost the ability to carry out transamination reactions. 
E)  All of the answers are correct. 
A)  nonessential amino acids are synthesized in simple reaction pathways compared to complex pathways for most essential amino acids. 
B)  essential amino acids are generally synthesized directly from citric acid cycle intermediates, but not nonessential amino acids. 
C)  microorganisms and animals cannot synthesize essential amino acids but plants can. 
D)  animals cannot synthesize essential amino acids because they have lost the ability to carry out transamination reactions. 
E)  All of the answers are correct. A

Question 3

Which of the following is a versatile carrier of several different one-carbon units?

Accepted Answer

A)  pyridoxal phosphate 
B)  biotin 
C)  tetrahydrofolate 
D)  coenzyme A 
E)  None of the answers is correct. 
A)  pyridoxal phosphate 
B)  biotin 
C)  tetrahydrofolate 
D)  coenzyme A 
E)  None of the answers is correct. C

Question 4

This amino acid,in high levels,is correlated with the damage of cells lining the blood vessels.

Accepted Answer

A)  serine 
B)  cysteine 
C)  S-adenosylmethionine 
D)  citrulline 
E)  homocysteine 
A)  serine 
B)  cysteine 
C)  S-adenosylmethionine 
D)  citrulline 
E)  homocysteine

Question 5

How does the herbicide glyphosate work?

Accepted Answer

Glyphosate (Roundup is one brand)acts by

Question 6

An example of a reaction controlled by enzyme multiplicity is

Accepted Answer

A)  phosphorylation of asparagine by aspartokinases. 
B)  phosphorylation of aspartate by aspartokinases. 
C)  phosphorylation of glutamine by glutamine synthetase. 
D)  all of the above. 
E)  None of the answers is correct. 
A)  phosphorylation of asparagine by aspartokinases. 
B)  phosphorylation of aspartate by aspartokinases. 
C)  phosphorylation of glutamine by glutamine synthetase. 
D)  all of the above. 
E)  None of the answers is correct.

Question 7

What is catalytic substrate channeling?

Accepted Answer

Channeling increases the catalytic rate,

Question 8

What molecule is an activated form of ribose phosphate and a precursor for histidine?

Accepted Answer

A)  ribose triphosphate 
B)  PRPP (5-phosphoribosyl-1-pyrophosphate) 
C)  ATP 
D)  cyclic AMP 
E)  None of the answers is correct. 
A)  ribose triphosphate 
B)  PRPP (5-phosphoribosyl-1-pyrophosphate) 
C)  ATP 
D)  cyclic AMP 
E)  None of the answers is correct.

Question 9

What unusual (and not recommended)experiments were carried out by Shemin and colleagues?

Accepted Answer

Acting as a human guinea pig,S

Question 10

Chorismate is a precursor to the amino acids

Accepted Answer

A)  tryptophan, tyrosine, and phenylalanine. 
B)  serine, glycine and cysteine. 
C)  isoleucine, leucine and valine. 
D)  methionine, threonine, and lysine. 
E)  None of the answers is correct. 
A)  tryptophan, tyrosine, and phenylalanine. 
B)  serine, glycine and cysteine. 
C)  isoleucine, leucine and valine. 
D)  methionine, threonine, and lysine. 
E)  None of the answers is correct.

Question 11

Describe the structure and function of the FeMo cofactor.

Accepted Answer

This unusual redox center is the site of

Question 12

Describe the process and proteins involved in nitrogen fixation.

Accepted Answer

Electrons are provided by ferredoxin,tra

Question 13

What do S-adenosylmethionine and fruit ripening have in common?

Accepted Answer

S-Adenosylmethionine is a prec

Question 14

What is the activated methyl cycle?

Accepted Answer

The methyl group on the side-chain of me

Question 15

Amino acid synthesis is primarily regulated by

Accepted Answer

A)  turnover. 
B)  diet. 
C)  urea excretion. 
D)  allosteric enzyme regulation. 
E)  All the answers are correct. 
A)  turnover. 
B)  diet. 
C)  urea excretion. 
D)  allosteric enzyme regulation. 
E)  All the answers are correct.

Question 16

What process converts N2 to NH3?

Accepted Answer

A)  urea cycle 
B)  glutamine hydrolysis 
C)  denitrification 
D)  nitrogen fixation 
E)  None of the answers is correct. 
A)  urea cycle 
B)  glutamine hydrolysis 
C)  denitrification 
D)  nitrogen fixation 
E)  None of the answers is correct.

Question 17

How may have feedback inhibition processes evolved?

Accepted Answer

A)  duplication of genes encoding catalytic domains 
B)  evolution of homologous subunits in the enzyme catalyzing the committed step 
C)  linking specific regulatory domains to catalytic domains 
D)  linking of multiple regulatory domains to one another 
E)  All of the answers are correct. 
A)  duplication of genes encoding catalytic domains 
B)  evolution of homologous subunits in the enzyme catalyzing the committed step 
C)  linking specific regulatory domains to catalytic domains 
D)  linking of multiple regulatory domains to one another 
E)  All of the answers are correct.

Question 18

Which of the following is a vasodilator that is derived from histidine?

Accepted Answer

A)  epinephrine 
B)  norepinephrine 
C)  histamine 
D)  adenosine 
E)  prostacyclin 
A)  epinephrine 
B)  norepinephrine 
C)  histamine 
D)  adenosine 
E)  prostacyclin

Question 19

Which of the following is the original nitrogen source for the nitrogen found in amino acids?

Accepted Answer

A)  atmospheric nitrogen (N2) 
B)  tetrahydrofolate 
C)  glutamine 
D)  ammonia (NH3) 
E)  urea 
A)  atmospheric nitrogen (N2) 
B)  tetrahydrofolate 
C)  glutamine 
D)  ammonia (NH3) 
E)  urea

Question 20

What amino acid is added to indole in the biosynthesis of tryptophan?

Accepted Answer

A)  glutamine 
B)  serine 
C)  tyrosine 
D)  alanine 
E)  None of the answers is correct. 
A)  glutamine 
B)  serine 
C)  tyrosine 
D)  alanine 
E)  None of the answers is correct.

Exam 24: The Biosynthesis of Amino Acids

The carbon skeletons used to synthesize amino acids are intermediates found in

Essential amino acids (for humans)differ from nonessential amino acids in that

Which of the following is a versatile carrier of several different one-carbon units?

This amino acid,in high levels,is correlated with the damage of cells lining the blood vessels.

How does the herbicide glyphosate work?

An example of a reaction controlled by enzyme multiplicity is

What is catalytic substrate channeling?

What molecule is an activated form of ribose phosphate and a precursor for histidine?

What unusual (and not recommended)experiments were carried out by Shemin and colleagues?

Chorismate is a precursor to the amino acids

Describe the structure and function of the FeMo cofactor.

Describe the process and proteins involved in nitrogen fixation.

What do S-adenosylmethionine and fruit ripening have in common?

What is the activated methyl cycle?

Amino acid synthesis is primarily regulated by

What process converts N2 to NH3?

How may have feedback inhibition processes evolved?

Which of the following is a vasodilator that is derived from histidine?

Which of the following is the original nitrogen source for the nitrogen found in amino acids?

What amino acid is added to indole in the biosynthesis of tryptophan?

Biochemistry: An Evolving Science

Protein Composition and Structure

Exploring Proteins and Proteomes

DNA, RNA, and the Flow of Genetic Information

Exploring Genes and Genomes

Exploring Evolution and Bioinformatics

Hemoglobin: a Portrait of a Protein in Action

Enzymes: Basic Concepts and Kinetics

Catalytic Strategies

Regulatory Strategies

Carbohydrates

Lipids and Cell Membranes

Membrane Channels and Pumps

Signal-Transduction Pathways

Metabolism: Basic Concepts and Design

Glycolysis and Gluconeogenesis

The Citric Acid Cycle

Oxidative Phosphorylation

The Light Reactions of Photosynthesis

The Calvin Cycle and the Pentose Phosphate Pathway

Glycogen Metabolism

Fatty Acid Metabolism

Protein Turnover and Amino Acid Catabolism

Nucleotide Biosynthesis

Biosynthesis of Membrane Lipids and Steroids

The Integration of Metabolism

DNA Replication, repair, and Recombination

RNA Synthesis and Processing

Protein Synthesis

The Control of Gene Expression in Prokaryotes

The Control of Gene Expression in Eukaryotes

Sensory Systems

The Immune System

Molecular Motors

Drug Development

Filters

What process converts N₂ to NH₃?