Question 1

What does a kinase do?

Accepted Answer

A kinase is an enzyme that catalyzes the

Question 2

Suppose you have discovered a new amino acid. Its R-group contains only carbon and hydrogen atoms. Predict the behavior of this amino acid.

Accepted Answer

A)  It is hydrophilic. 
B)  It is hydrophobic. 
C)  It is polar. 
D)  Its R-group is positively charged at physiological pH. 
A)  It is hydrophilic. 
B)  It is hydrophobic. 
C)  It is polar. 
D)  Its R-group is positively charged at physiological pH.

Question 3

Amino acids are joined by a condensation reaction to form a polypeptide chain with a ___________ backbone and ___________ side chain.

Accepted Answer

A)  variable, common 
B)  variable, variable 
C)  common, variable 
D)  common, common 
A)  variable, common 
B)  variable, variable 
C)  common, variable 
D)  common, common

Question 4

Proline is a "helix-breaking" residue because

Accepted Answer

A)  its R-group is too large to be accommodated in the alpha helix interior 
B)  its R-group is too hydrophobic to interact with water surrounding the alpha helix 
C)  its backbone nitrogen can only form hydrogen bonds in the context of a pleated beta sheet 
D)  cyclization prevents its backbone nitrogen from participating in hydrogen bonding that stabilizes the helix 
A)  its R-group is too large to be accommodated in the alpha helix interior 
B)  its R-group is too hydrophobic to interact with water surrounding the alpha helix 
C)  its backbone nitrogen can only form hydrogen bonds in the context of a pleated beta sheet 
D)  cyclization prevents its backbone nitrogen from participating in hydrogen bonding that stabilizes the helix

Question 5

Allosteric regulation always involves

Accepted Answer

A)  a change in protein shape or conformation. 
B)  a post-translational modification. 
C)  interaction with Hsp90. 
D)  the ubiquitin-proteasome system. 
A)  a change in protein shape or conformation. 
B)  a post-translational modification. 
C)  interaction with Hsp90. 
D)  the ubiquitin-proteasome system.

Question 6

Which level(s) of protein structure could be disrupted by treatment with a reducing agent?

Accepted Answer

A)  primary 
B)  primary and secondary 
C)  tertiary 
D)  tertiary and quaternary 
A)  primary 
B)  primary and secondary 
C)  tertiary 
D)  tertiary and quaternary

Question 7

_____________ different genetically-encoded amino acids are found in the proteins of cells; they are distinguished by___________________ .

Accepted Answer

A)  22; the location of their carboxyl group 
B)  20; the location of their amino group 
C)  20; the angles between the central carbon and their side chains, or R-groups 
D)  22; the composition of their side chains, or R-groups 
A)  22; the location of their carboxyl group 
B)  20; the location of their amino group 
C)  20; the angles between the central carbon and their side chains, or R-groups 
D)  22; the composition of their side chains, or R-groups

Question 8

Cyclin-dependent kinase activity is regulated by

Accepted Answer

A)  phosphorylation. 
B)  allosteric modification. 
C)  allolactose. 
D)  both A and B 
A)  phosphorylation. 
B)  allosteric modification. 
C)  allolactose. 
D)  both A and B

Question 9

Which amino acid shown below, glutamine or valine, would be more likely to be found within the membrane region of a transmembrane protein, and less likely to be found in the intracellular region?

Accepted Answer

A)  Glutamine 
B)  Valine 
A)  Glutamine 
B)  Valine

Question 10

Describe two possible fates for a misfolded protein in a cell.

Accepted Answer

Two of the more common outcomes are (1)

Question 11

The sequence of a portion of a gene is presented below:
5′-AGCAATGCATGCATCGTTATGG-3′
3′-TCGTTACGTACGTAGCAATACC-5′
(a) Assuming that transcription starts with the first T in the template strand of the DNA, and continues to the end, what would be the sequence of the transcribed mRNA?
(b) Identify the initiation codon in this mRNA.
(c) Would there be an effect on translation of changing the first C in the template strand to a G? If so, what effect?
(d) Would there be an effect on translation of changing the third G in the template strand to a T? If so, what effect?
(e) Would there be an effect on translation of changing the last A in the template strand to a C? If so, what effect?
(f) Would there be an effect on translation if pyrrolysine were present?

Accepted Answer

(a) 5′-AGCAAUGCAUGCAUCGUUAUGG-3′
(b) AUG

Question 12

An enzyme's active site usually

Accepted Answer

A)  is on the outer surface of an enzyme. 
B)  is hydrophobic. 
C)  forms a cleft or pocket in the enzyme. 
D)  undergoes irreversible modification during catalysis. 
A)  is on the outer surface of an enzyme. 
B)  is hydrophobic. 
C)  forms a cleft or pocket in the enzyme. 
D)  undergoes irreversible modification during catalysis.

Question 13

In a beta-pleated sheet,

Accepted Answer

A)  adjacent polypeptide strands interact in an extended conformation 
B)  beta strands stack at perpendicular angles 
C)  R-groups of hydrophobic amino acids stabilize adjacent stretches of amino acid residues 
D)  alpha helices align in parallel or antiparallel arrays 
A)  adjacent polypeptide strands interact in an extended conformation 
B)  beta strands stack at perpendicular angles 
C)  R-groups of hydrophobic amino acids stabilize adjacent stretches of amino acid residues 
D)  alpha helices align in parallel or antiparallel arrays

Question 14

Do UAG, UAA, and UGA always act as termination codons during protein synthesis? Explain your answer.

Accepted Answer

No, UAG, UAA, and UGA do not always act

Question 15

Which of the following are rare amino acids that are sometimes encoded by stop codons?

Accepted Answer

A)  isoleucine and pyrroglutamine 
B)  selenocysteine and pyrrolysine 
C)  pseudouridine and D-alanine 
D)  abrine and homocysteine 
A)  isoleucine and pyrroglutamine 
B)  selenocysteine and pyrrolysine 
C)  pseudouridine and D-alanine 
D)  abrine and homocysteine

Question 16

At the pH found in cells (about 7.0), what happens to the carboxyl group on an amino acid?

Accepted Answer

A)  It acts as a base and gains a proton, giving it a positive charge. 
B)  It acts as an acid and loses a proton, giving it a positive charge. 
C)  It acts as an acid and loses a proton, giving it a negative charge. 
D)  It neither gains nor loses a proton and does not have a charge. 
A)  It acts as a base and gains a proton, giving it a positive charge. 
B)  It acts as an acid and loses a proton, giving it a positive charge. 
C)  It acts as an acid and loses a proton, giving it a negative charge. 
D)  It neither gains nor loses a proton and does not have a charge.

Question 17

An enzyme that catalyzes phosphorylation of a substrate is called

Accepted Answer

A)  a kinase. 
B)  a transferase. 
C)  a phosphoprotein. 
D)  a glycoprotein. 
A)  a kinase. 
B)  a transferase. 
C)  a phosphoprotein. 
D)  a glycoprotein.

Question 18

Many steps in gene expression and cell signaling involve post-translational modification of proteins by

Accepted Answer

A)  reversible disulfide bridge formation. 
B)  irreversible disulfide bridge formation. 
C)  reversible phosphorylation. 
D)  irreversible phosphorylation. 
A)  reversible disulfide bridge formation. 
B)  irreversible disulfide bridge formation. 
C)  reversible phosphorylation. 
D)  irreversible phosphorylation.

Question 19

The following is a short segment of an mRNA molecule. The polypeptide it codes for is also shown:
5 ' AUGGUGCUGAAG 3 ': methionine-valine-leucine-lysine
A mutation in the DNA occurs so that the fourth base (counting from the 5 ' end) in the messenger RNA now reads A rather than G. What sequence of peptides will the mRNA now code for? (You do not need a copy of the genetic code to answer the question.)
A) methionine-lysine-leucine-lysine
B) methionine-leucine-leucine-lysine
C) methionine-valine-methionine-lysine
D) methionine-methionine-leucine-lysine

Accepted Answer

The answer of The following is a short segment of...

Question 20

Extrapolating from the example of lysozyme, which part of an enzyme do you suppose directly promotes catalysis?

Accepted Answer

A)  the peptide backbone 
B)  amino acid side chains 
C)  alpha helices 
D)  the hydrophobic core 
A)  the peptide backbone 
B)  amino acid side chains 
C)  alpha helices 
D)  the hydrophobic core

What does a kinase do?

Suppose you have discovered a new amino acid. Its R-group contains only carbon and hydrogen atoms. Predict the behavior of this amino acid.

Amino acids are joined by a condensation reaction to form a polypeptide chain with a _ backbone and _ side chain.

Proline is a "helix-breaking" residue because

Allosteric regulation always involves

Which level(s) of protein structure could be disrupted by treatment with a reducing agent?

_ different genetically-encoded amino acids are found in the proteins of cells; they are distinguished by_______ .

Cyclin-dependent kinase activity is regulated by

Which amino acid shown below, glutamine or valine, would be more likely to be found within the membrane region of a transmembrane protein, and less likely to be found in the intracellular region?

Describe two possible fates for a misfolded protein in a cell.

An enzyme's active site usually

In a beta-pleated sheet,

Do UAG, UAA, and UGA always act as termination codons during protein synthesis? Explain your answer.

Which of the following are rare amino acids that are sometimes encoded by stop codons?

At the pH found in cells (about 7.0), what happens to the carboxyl group on an amino acid?

An enzyme that catalyzes phosphorylation of a substrate is called

Many steps in gene expression and cell signaling involve post-translational modification of proteins by

Extrapolating from the example of lysozyme, which part of an enzyme do you suppose directly promotes catalysis?

The Beginnings of Molecular Biology

The Structure of DNA

The Versatility of RNA

Genome Organization and Evolution

DNA Replication and Telomere Maintenance

DNA Repair Pathways

Recombinant Dna Technology and Molecular Cloning

Tools for Analyzing Gene Expression

Transcription in Bacteria

Transcription in Eukaryotes

Epigenetic Mechanisms of Gene Regulation

RNA Processing and Post-Transcriptional Gene Regulation

The Mechanism of Translation

Genetically Modified Organisms: Use in Basic and Applied Research

Genome Analysis: DNA Typing, Genomics, and Beyond

Medical Molecular Biology

Filters

Exam 4: Protein Structure and Folding

What does a kinase do?

Suppose you have discovered a new amino acid. Its R-group contains only carbon and hydrogen atoms. Predict the behavior of this amino acid.

Amino acids are joined by a condensation reaction to form a polypeptide chain with a ___________ backbone and ___________ side chain.

Proline is a "helix-breaking" residue because

Allosteric regulation always involves

Which level(s) of protein structure could be disrupted by treatment with a reducing agent?

_____________ different genetically-encoded amino acids are found in the proteins of cells; they are distinguished by___________________ .

Cyclin-dependent kinase activity is regulated by

Which amino acid shown below, glutamine or valine, would be more likely to be found within the membrane region of a transmembrane protein, and less likely to be found in the intracellular region?

Describe two possible fates for a misfolded protein in a cell.

An enzyme's active site usually

In a beta-pleated sheet,

Do UAG, UAA, and UGA always act as termination codons during protein synthesis? Explain your answer.

Which of the following are rare amino acids that are sometimes encoded by stop codons?

At the pH found in cells (about 7.0), what happens to the carboxyl group on an amino acid?

An enzyme that catalyzes phosphorylation of a substrate is called

Many steps in gene expression and cell signaling involve post-translational modification of proteins by

Extrapolating from the example of lysozyme, which part of an enzyme do you suppose directly promotes catalysis?

The Beginnings of Molecular Biology

The Structure of DNA

The Versatility of RNA

Genome Organization and Evolution

DNA Replication and Telomere Maintenance

DNA Repair Pathways

Recombinant Dna Technology and Molecular Cloning

Tools for Analyzing Gene Expression

Transcription in Bacteria

Transcription in Eukaryotes

Epigenetic Mechanisms of Gene Regulation

RNA Processing and Post-Transcriptional Gene Regulation

The Mechanism of Translation

Genetically Modified Organisms: Use in Basic and Applied Research

Genome Analysis: DNA Typing, Genomics, and Beyond

Medical Molecular Biology

Filters

Amino acids are joined by a condensation reaction to form a polypeptide chain with a _ backbone and _ side chain.

_ different genetically-encoded amino acids are found in the proteins of cells; they are distinguished by_______ .