Question 1

Which of the following enzymes catalyze the unwinding of the DNA double helix?

Accepted Answer

A) topoisomerases 
B) helicases 
C) ligases 
D) gyrases 
A) topoisomerases 
B) helicases 
C) ligases 
D) gyrases

Question 2

What explains why progeny may have new combinations of traits compared to their parents?

Accepted Answer

A) reverse transcriptase 
B) cyclin-dependent protein kinase 
C) genetic recombination 
D) processivity 
A) reverse transcriptase 
B) cyclin-dependent protein kinase 
C) genetic recombination 
D) processivity

Question 3

Which of the following is NOT an activity the reverse transcriptases possess?

Accepted Answer

A) DNA ligase activity 
B) RNA-directed DNA polymerase activity 
C) RNase H activity 
D) DNA-directed DNA polymerase activity 
A) DNA ligase activity 
B) RNA-directed DNA polymerase activity 
C) RNase H activity 
D) DNA-directed DNA polymerase activity

Question 4

Which of the following is a characteristic of replication of the E.coli circular chromosome?

Accepted Answer

A) Replication is unidirectional. 
B) It initiates at a random position. 
C) The unwinding of the duplex DNA is driven by the translocation of the DNA polymerase. 
D) Torsional stress introduced in the duplex DNA is relieved by DNA gyrase. 
A) Replication is unidirectional. 
B) It initiates at a random position. 
C) The unwinding of the duplex DNA is driven by the translocation of the DNA polymerase. 
D) Torsional stress introduced in the duplex DNA is relieved by DNA gyrase.

Question 5

Progression through the cell cycle for eukaryotic cells is regulated through a series of checkpoints that depend on cyclins.Which of the following components do cyclins bind that can then regulate specific proteins by phosphorylation?

Accepted Answer

A) cyclin-dependent protein kinases (CDKs) 
B) protein kinases 
C) cyclin-dependent inhibitors 
D) cAMPs 
A) cyclin-dependent protein kinases (CDKs) 
B) protein kinases 
C) cyclin-dependent inhibitors 
D) cAMPs

Question 6

Which of the following regions of immunoglobulins forms the structural site complementary to some part of an antigen's structure?

Accepted Answer

A) immunoglobulin fold 
B) hypervariable 
C) hinge 
D) constant heavy 
A) immunoglobulin fold 
B) hypervariable 
C) hinge 
D) constant heavy

Question 7

Which of the following explains how the vast diversity of immunoglobulin sequences are created?

Accepted Answer

A) by DNA rearrangement 
B) by large sections of DNA devoted to immunoglobulin formation 
C) by susceptibility of the immunoglobulin genes to mutation 
D) by sensitivity of formed immunoglobulin proteins to environmental factors 
A) by DNA rearrangement 
B) by large sections of DNA devoted to immunoglobulin formation 
C) by susceptibility of the immunoglobulin genes to mutation 
D) by sensitivity of formed immunoglobulin proteins to environmental factors

Question 8

BRCA1 protein functions in regulation of the cell cycle in response to DNA damage control,and BRCA2 protein participates in DNA repair by homologous recombination.Which of the following type(s)of cancers can occur as a result of mutations in BRCA1 and BRCA2 genes?

Accepted Answer

A) breast and ovarian 
B) uterine 
C) prostate 
D) lung 
A) breast and ovarian 
B) uterine 
C) prostate 
D) lung

Question 9

Which of the following characteristics refers to the degree to which the enzyme remains associated with the template through successive cycles of nucleotide addition?

Accepted Answer

A) processivity 
B) turn-over number 
C) progression 
D) semidiscontinuousness 
A) processivity 
B) turn-over number 
C) progression 
D) semidiscontinuousness

Question 10

In base-excision repair,the first enzyme in the sequence is DNA glycosylase.Which of the following types of sites does the enzyme create?

Accepted Answer

A) ligase binding 
B) apurinic or apyrimidinic 
C) DNA polymerase I 
D) DNA polymerase III binding 
A) ligase binding 
B) apurinic or apyrimidinic 
C) DNA polymerase I 
D) DNA polymerase III binding

Question 11

Which of the following is a characteristic of telomeres?

Accepted Answer

A) G-rich nucleotide sequences 
B) structures at the end of eukaryotic chromosomes 
C) eukaryotic counterpart to the prokaryotic g-complex 
D) short (5-8 bp)tandemly repeated sequences 
A) G-rich nucleotide sequences 
B) structures at the end of eukaryotic chromosomes 
C) eukaryotic counterpart to the prokaryotic g-complex 
D) short (5-8 bp)tandemly repeated sequences

Question 12

Which of the following types of mutations most likely results from the alkylation of the oxygen on position 6 of guanine base,producing O⁶-methylguanine?

Accepted Answer

A) deletion 
B) insertion 
C) transition 
D) frameshift 
A) deletion 
B) insertion 
C) transition 
D) frameshift

Question 13

Which of the following is NOT a characteristic of RNA-directed DNA polymerase?

Accepted Answer

A) often uses a specific tRNA primer 
B) found in retroviruses 
C) synthesizes polynucleotides in the 3' to 5' direction 
D) also called reverse transcriptase 
A) often uses a specific tRNA primer 
B) found in retroviruses 
C) synthesizes polynucleotides in the 3' to 5' direction 
D) also called reverse transcriptase

Question 14

Which of the following is a function of the RecA protein in recombination events?

Accepted Answer

A) to produce an endonucleolytic nick on dsDNA 
B) to aid in recognition of Chi site by the RecBCD complex 
C) to initiate recombination 
D) to catalyze the ATP-dependent DNA strand exchange reaction 
A) to produce an endonucleolytic nick on dsDNA 
B) to aid in recognition of Chi site by the RecBCD complex 
C) to initiate recombination 
D) to catalyze the ATP-dependent DNA strand exchange reaction

Question 15

Which of the following processes provides a mechanism for generating a variety of protein isoforms of immunoglobulins from a limited number of genes?

Accepted Answer

A) genetic recombination 
B) DNA rearrangement 
C) replication licensing 
D) DNA ligation 
A) genetic recombination 
B) DNA rearrangement 
C) replication licensing 
D) DNA ligation

Question 16

Which of the following carries out removal of RNA primer,followed by replacement with DNA?

Accepted Answer

A) DNA polymerase I 
B) DNA gyrase 
C) DNA polymerase III 
D) DNA ligase 
A) DNA polymerase I 
B) DNA gyrase 
C) DNA polymerase III 
D) DNA ligase

Question 17

Which of the following occurs during DNA replication in E.coli?

Accepted Answer

A) Primase (DnaG)binds to a GC-rich region of dsDNA in oriC. 
B) Helicase unwinds dsDNA downstream of the replication fork. 
C) DNA ligase catalyzes the formation of phosphoester bonds on the leading strand. 
D) DNA polymerase I hydrolyzes RNA from the 5' ends of Okazaki fragments. 
A) Primase (DnaG)binds to a GC-rich region of dsDNA in oriC. 
B) Helicase unwinds dsDNA downstream of the replication fork. 
C) DNA ligase catalyzes the formation of phosphoester bonds on the leading strand. 
D) DNA polymerase I hydrolyzes RNA from the 5' ends of Okazaki fragments.

Question 18

Which of the following types of mutation causes misincorporation of all subsequent amino acids?

Accepted Answer

A) chemical 
B) base shift 
C) frameshift 
D) transition 
A) chemical 
B) base shift 
C) frameshift 
D) transition

Exam 28: DNA Metabolism: Replication, recombination, and Repair

Which of the following enzymes catalyze the unwinding of the DNA double helix?

What explains why progeny may have new combinations of traits compared to their parents?

Which of the following is NOT an activity the reverse transcriptases possess?

Which of the following is a characteristic of replication of the E.coli circular chromosome?

Progression through the cell cycle for eukaryotic cells is regulated through a series of checkpoints that depend on cyclins.Which of the following components do cyclins bind that can then regulate specific proteins by phosphorylation?

Which of the following regions of immunoglobulins forms the structural site complementary to some part of an antigen's structure?

Which of the following explains how the vast diversity of immunoglobulin sequences are created?

BRCA1 protein functions in regulation of the cell cycle in response to DNA damage control,and BRCA2 protein participates in DNA repair by homologous recombination.Which of the following type(s)of cancers can occur as a result of mutations in BRCA1 and BRCA2 genes?

Which of the following characteristics refers to the degree to which the enzyme remains associated with the template through successive cycles of nucleotide addition?

In base-excision repair,the first enzyme in the sequence is DNA glycosylase.Which of the following types of sites does the enzyme create?

Which of the following is a characteristic of telomeres?

Which of the following types of mutations most likely results from the alkylation of the oxygen on position 6 of guanine base,producing O⁶-methylguanine?

Which of the following is NOT a characteristic of RNA-directed DNA polymerase?

Which of the following is a function of the RecA protein in recombination events?

Which of the following processes provides a mechanism for generating a variety of protein isoforms of immunoglobulins from a limited number of genes?

Which of the following carries out removal of RNA primer,followed by replacement with DNA?

Which of the following occurs during DNA replication in E.coli?

Which of the following types of mutation causes misincorporation of all subsequent amino acids?

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

Water: the Medium of Life

Thermodynamics of Biological Systems

Amino Acids

Proteins: Their Primary Structure and Biological Functions

Proteins: Secondary, tertiary, and Quaternary Structure

Carbohydrates and the Glycoconjugates of Cell Surfaces

Lipids

Lipid Biosynthesis

Membranes and Membrane Transport

The Reception and Transmission of Extracellular Information

Enzymes Kinetics and Specificity

Mechanisms of Enzyme Action

Enzyme Regulation

Molecular Motors

Nutrition and the Organization of Metabolism

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

Nucleotides and Nucleic Acids

Structure of Nucleic Acids

Synthesis and Degradation of Nucleotides

Recombinant Dna: Cloning and Creation of Chimeric Genes

Transcription and the Regulation of Gene Expression

Protein Synthesis

Post-Transcriptional Regulation of Gene Expression

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

Metabolic Integration and Organ Specialization

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