Question 1

Figure 6.3 is a diagram of DNA replication at a replication fork.   The strand labeled C is:

Accepted Answer

A) The template strand. 
B) The leading strand. 
C) The RNA primer. 
D) The lagging strand. 
E) The Holliday intermediate. 
A) The template strand. 
B) The leading strand. 
C) The RNA primer. 
D) The lagging strand. 
E) The Holliday intermediate. D

Question 2

Which of the following bases, when it occurs in the wobble position in tRNA, can bind to three different bases (adenine [A], uracil [U], and cytosine [C])?

Accepted Answer

A) Cytosine. 
B) Hypoxanthine. 
C) Adenine. 
D) Guanine. 
E) Uracil. 
A) Cytosine. 
B) Hypoxanthine. 
C) Adenine. 
D) Guanine. 
E) Uracil. B

Question 3

Unlike DNA polymerases, RNA polymerases:

Accepted Answer

A) Can elongate a primer oligonucleotide. 
B) Can initiate synthesis of their polynucleotide product. 
C) Generate inorganic pyrophosphate. 
D) Have 3'-exonuclease activity. 
E) Require a separate helicase enzyme for strand separation before they can start synthesizing their product. 
A) Can elongate a primer oligonucleotide. 
B) Can initiate synthesis of their polynucleotide product. 
C) Generate inorganic pyrophosphate. 
D) Have 3'-exonuclease activity. 
E) Require a separate helicase enzyme for strand separation before they can start synthesizing their product. B

Question 4

A promoter region of a gene is best described as:

Accepted Answer

A) A purine-rich sequence downstream from the start site of transcription. 
B) A ribosome-binding site on the mRNA. 
C) A site where RNA polymerases bind to DNA to initiate transcription. 
D) A site where repressors bind to RNA polymerase to terminate transcription. 
E) The first transcribed segment of the gene. 
A) A purine-rich sequence downstream from the start site of transcription. 
B) A ribosome-binding site on the mRNA. 
C) A site where RNA polymerases bind to DNA to initiate transcription. 
D) A site where repressors bind to RNA polymerase to terminate transcription. 
E) The first transcribed segment of the gene.

Question 5

Which of the radiolabeled oligonucleotide probes below would best hybridize with the DNA sequence 5'-AAAAGGTTCC-3'?

Accepted Answer

A) 32P-5'-CCTTGGAAAA-3'. 
B) 32P-5'-AAAAGGTTCC-3'. 
C) 32P-5'-TTTTCCAAGG-3'. 
D) 32P-5'-GGAACCTTTT-3'. 
E) 32P-5'-UUUUCCAAGG-3'. 
A) 32P-5'-CCTTGGAAAA-3'. 
B) 32P-5'-AAAAGGTTCC-3'. 
C) 32P-5'-TTTTCCAAGG-3'. 
D) 32P-5'-GGAACCTTTT-3'. 
E) 32P-5'-UUUUCCAAGG-3'.

Question 6

The consensus sequences of prokaryotic promoters are recognized by:

Accepted Answer

A) RNA polymerase core enzyme. 
B) The TATA-binding protein. 
C) The β´ subunit of RNA polymerase. 
D) The σ subunit of RNA polymerase. 
E) Small nuclear ribonucleoprotein particles. 
A) RNA polymerase core enzyme. 
B) The TATA-binding protein. 
C) The β´ subunit of RNA polymerase. 
D) The σ subunit of RNA polymerase. 
E) Small nuclear ribonucleoprotein particles.

Question 7

The lac operon is induced by the presence of lactose, but it is transcribed at a high rate only when:

Accepted Answer

A) The cyclic adenosine monophosphate (cAMP) level in the cell is high. 
B) A ribosome binds to the Shine-Dalgarno sequence. 
C) A ribosome binds to the 5' cap of the mRNA. 
D) Tryptophan is present in high concentration. 
E) Glucose is present 
A) The cyclic adenosine monophosphate (cAMP) level in the cell is high. 
B) A ribosome binds to the Shine-Dalgarno sequence. 
C) A ribosome binds to the 5' cap of the mRNA. 
D) Tryptophan is present in high concentration. 
E) Glucose is present

Question 8

Which of the following components is a cytoplasmic protein that transiently associates with the ribosome?

Accepted Answer

A) Shine-Dalgarno sequence. 
B) The catabolite activator protein (CAP). 
C) Elongation factor G. 
D) Peptidyl transferase. 
E) Aminoacyl-tRNA synthetase. 
A) Shine-Dalgarno sequence. 
B) The catabolite activator protein (CAP). 
C) Elongation factor G. 
D) Peptidyl transferase. 
E) Aminoacyl-tRNA synthetase.

Question 9

Mutations are hazardous to the health of E.coli (and Homo sapiens as well).To reduce this health hazard, E.coli employs:

Accepted Answer

A) The 3' --> 5' endonuclease activity of DNA polymerase I. 
B) The 5' --> 3' exonuclease activity of DNA polymerase III. 
C) The 3' --> 5' exonuclease activity of DNA polymerase III. 
D) The 3'--> 5' exonuclease activity of DNA polymerase II. 
E) The 5' --> 3' endonuclease activity of DNA polymerase I. 
A) The 3' --> 5' endonuclease activity of DNA polymerase I. 
B) The 5' --> 3' exonuclease activity of DNA polymerase III. 
C) The 3' --> 5' exonuclease activity of DNA polymerase III. 
D) The 3'--> 5' exonuclease activity of DNA polymerase II. 
E) The 5' --> 3' endonuclease activity of DNA polymerase I.

Question 10

The purpose of the gene products of the lac operon is to ___________.The purpose of the gene products of the trp operon is to ___________.

Accepted Answer

A) Produce lactose when glucose is low; produce tryptophan when tryptophan is low. 
B) Produce lactose when lactose is low; produce tryptophan when glucose is low. 
C) Produce lactose when glucose is low; metabolize tryptophan for energy. 
D) Metabolize lactose when glucose is low; metabolize tryptophan for energy. 
E) Metabolize lactose when glucose is low; produce tryptophan when tryptophan is low. 
A) Produce lactose when glucose is low; produce tryptophan when tryptophan is low. 
B) Produce lactose when lactose is low; produce tryptophan when glucose is low. 
C) Produce lactose when glucose is low; metabolize tryptophan for energy. 
D) Metabolize lactose when glucose is low; metabolize tryptophan for energy. 
E) Metabolize lactose when glucose is low; produce tryptophan when tryptophan is low.

Question 11

In a particular bacterial operon, there are two genes that are transcribed into one mRNA transcript.In order, how many promoter regions, how many ribosomal binding sites, how many AUG initiation codons, and how many stop codons do you expect to find in the operon or its mRNA?

Accepted Answer

A) 2, 2, 2, 2. 
B) 2, 1, 1, 1. 
C) 2, 2, 2, 1. 
D) 1, 1, 1, 1. 
E) 1, 2, 2, 2. 
A) 2, 2, 2, 2. 
B) 2, 1, 1, 1. 
C) 2, 2, 2, 1. 
D) 1, 1, 1, 1. 
E) 1, 2, 2, 2.

Question 12

During DNA replication, which type of enzyme separates double-stranded DNA into the single-stranded DNA that is needed as a template for the DNA polymerases?

Accepted Answer

A) DNase. 
B) Topoisomerase. 
C) Helicase. 
D) Primase. 
E) Single-stranded DNA binding (SS
B)  protein. 
A) DNase. 
B) Topoisomerase. 
C) Helicase. 
D) Primase. 
E) Single-stranded DNA binding (SS
B)  protein.

Question 13

Translation is terminated by a release factor (RF) and:

Accepted Answer

A) Rho. 
B) A stem-loop structure. 
C) UGA, UAG, or UAA codons. 
D) AUG codons. 
E) Consecutive trp codons. 
A) Rho. 
B) A stem-loop structure. 
C) UGA, UAG, or UAA codons. 
D) AUG codons. 
E) Consecutive trp codons.

Question 14

Inhibitors of DNA replication are most likely to find medical use as:

Accepted Answer

A) Antifungal agents. 
B) Treatments for immunodeficiency diseases. 
C) Antibiotics. 
D) Anticancer drugs. 
E) Treatments for psychiatric conditions such as schizophrenia. 
A) Antifungal agents. 
B) Treatments for immunodeficiency diseases. 
C) Antibiotics. 
D) Anticancer drugs. 
E) Treatments for psychiatric conditions such as schizophrenia.

Question 15

Under conditions in which methionine must be the first amino acid, what protein would be coded for by the following mRNA? 5'-CCUCAUAUGCGCCAUUAUAAGUGACACACA-3'

Accepted Answer

A) Pro-His-Met-Arg-His-Tyr-Lys-Cys-His-Thr. 
B) Met-Arg-His-Tyr-Lys-Cys-His-Thr. 
C) Met-Arg-His-Tyr-Lys. 
D) Met-Pro-His-Met-Arg-His-Tyr-Lys-Cys-His-Thr. 
E) Arg-His-Ser-Glu-Tyr-Tyr-Arg-Leu-Tyr-Ser. 
A) Pro-His-Met-Arg-His-Tyr-Lys-Cys-His-Thr. 
B) Met-Arg-His-Tyr-Lys-Cys-His-Thr. 
C) Met-Arg-His-Tyr-Lys. 
D) Met-Pro-His-Met-Arg-His-Tyr-Lys-Cys-His-Thr. 
E) Arg-His-Ser-Glu-Tyr-Tyr-Arg-Leu-Tyr-Ser.

Question 16

Where is the regulation of gene expression most likely to occur?

Accepted Answer

A) At initiation of translation. 
B) Post-translationally. 
C) At initiation of DNA replication. 
D) At termination of transcription. 
E) At initiation of transcription. 
A) At initiation of translation. 
B) Post-translationally. 
C) At initiation of DNA replication. 
D) At termination of transcription. 
E) At initiation of transcription.

Question 17

During DNA replication, the many RNA primers found in the lagging strand must be removed.Which enzyme performs this task in E.coli?

Accepted Answer

A) RNAse A. 
B) Helicase. 
C) RNA polymerase II. 
D) DNA polymerase I. 
E) DNA polymerase III. 
A) RNAse A. 
B) Helicase. 
C) RNA polymerase II. 
D) DNA polymerase I. 
E) DNA polymerase III.

Question 18

Which of the following correctly describes the structure of the DNA double helix?

Accepted Answer

A) The bases are in the center of the double helix and do not contact the surrounding water. 
B) 2-Deoxyribose forms O-glycosidic bonds. 
C) All hydroxyl groups of 2-deoxyribose are tied up in covalent bonds. 
D) The purine and pyrimidine bases carry positive charges at a pH of 7. 
E) The double helix can interact with proteins mainly through hydrophobic interactions. 
A) The bases are in the center of the double helix and do not contact the surrounding water. 
B) 2-Deoxyribose forms O-glycosidic bonds. 
C) All hydroxyl groups of 2-deoxyribose are tied up in covalent bonds. 
D) The purine and pyrimidine bases carry positive charges at a pH of 7. 
E) The double helix can interact with proteins mainly through hydrophobic interactions.

Question 19

With what messenger RNA (mRNA) codon would the transfer RNA (tRNA) in the diagram be able to form a codon-anticodon base pairing interaction?

Accepted Answer

A) 5'-AUG-3'. 
B) 5'-GUA-3'. 
C) 5'-UAC-3'. 
D) 5'-CAU-3'. 
E) 5'-GAU-3'. 
A) 5'-AUG-3'. 
B) 5'-GUA-3'. 
C) 5'-UAC-3'. 
D) 5'-CAU-3'. 
E) 5'-GAU-3'.

Question 20

Which of the following does not have an ATP or GTP requirement?

Accepted Answer

A) Attachment of an amino acid to its tRNA. 
B) Placement of a new aminoacyl-tRNA on the ribosome during elongation. 
C) Movement of the ribosome along the mRNA. 
D) Formation of the peptide bond during protein synthesis. 
E) Assembly of the translational initiation complex. 
A) Attachment of an amino acid to its tRNA. 
B) Placement of a new aminoacyl-tRNA on the ribosome during elongation. 
C) Movement of the ribosome along the mRNA. 
D) Formation of the peptide bond during protein synthesis. 
E) Assembly of the translational initiation complex.

Exam 6: DNA, RNA, and Protein Synthesis

Figure 6.3 is a diagram of DNA replication at a replication fork. The strand labeled C is:

Which of the following bases, when it occurs in the wobble position in tRNA, can bind to three different bases (adenine [A], uracil [U], and cytosine [C])?

Unlike DNA polymerases, RNA polymerases:

A promoter region of a gene is best described as:

Which of the radiolabeled oligonucleotide probes below would best hybridize with the DNA sequence 5'-AAAAGGTTCC-3'?

The consensus sequences of prokaryotic promoters are recognized by:

The lac operon is induced by the presence of lactose, but it is transcribed at a high rate only when:

Which of the following components is a cytoplasmic protein that transiently associates with the ribosome?

Mutations are hazardous to the health of E.coli (and Homo sapiens as well).To reduce this health hazard, E.coli employs:

The purpose of the gene products of the lac operon is to ___________.The purpose of the gene products of the trp operon is to ___________.

In a particular bacterial operon, there are two genes that are transcribed into one mRNA transcript.In order, how many promoter regions, how many ribosomal binding sites, how many AUG initiation codons, and how many stop codons do you expect to find in the operon or its mRNA?

During DNA replication, which type of enzyme separates double-stranded DNA into the single-stranded DNA that is needed as a template for the DNA polymerases?

Translation is terminated by a release factor (RF) and:

Inhibitors of DNA replication are most likely to find medical use as:

Under conditions in which methionine must be the first amino acid, what protein would be coded for by the following mRNA? 5'-CCUCAUAUGCGCCAUUAUAAGUGACACACA-3'

Where is the regulation of gene expression most likely to occur?

During DNA replication, the many RNA primers found in the lagging strand must be removed.Which enzyme performs this task in E.coli?

Which of the following correctly describes the structure of the DNA double helix?

With what messenger RNA (mRNA) codon would the transfer RNA (tRNA) in the diagram be able to form a codon-anticodon base pairing interaction?

Which of the following does not have an ATP or GTP requirement?

Introduction to Biomolecules

Introduction to Protein Structure

Oxygen Transporters: Hemoglobin and Myoglobin

Enzymatic Reactions

Coenzymes

The Human Genome

Protein Targeting

Introduction to Genetic Diseases

Viruses

DNA Technology

Biological Membranes

The Cytoskeleton

The Extracellular Matrix

Plasma Proteins

Extracellular Messengers

Intracellular Messengers

Cellular Growth Control and Cancer

Digestive Enzymes

Introduction to Metabolic Pathways

Glycolysis, Tricarboxylic Acid Cycle, and Oxidative Phosphorylation

Carbohydrate Metabolism

The Metabolism of Fatty Acids and Triglycerides

The Metabolism of Membrane Lipids

Lipid Transport

Amino Acid Metabolism

Heme Metabolism

The Metabolism of Purines and Pyrimidines

Vitamins and Minerals

Integration of Metabolism

Filters

The purpose of the gene products of the lac operon is to _.The purpose of the gene products of the trp operon is to _.