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Chapter 11: Mechanisms of Microbial Genetics

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Chapter 11: Mechanisms of Microbial Genetics

48 problems · 0 figures

11-1 §11.MC source ↗

DNA does all but which of the following?
  1. a.
    serves as the genetic material passed from parent to offspring
  2. b.
    remains constant despite changes in environmental conditions
  3. c.
    provides the instructions for the synthesis of messenger RNA
  4. d.
    is read by ribosomes during the process of translation

Answer

D. is read by ribosomes during the process of translation

11-2 §11.MC source ↗

According to the central dogma, which of the following represents the flow of genetic information in cells?
  1. a.
    protein to DNA to RNA
  2. b.
    DNA to RNA to protein
  3. c.
    RNA to DNA to protein
  4. d.
    DNA to protein to RNA

Answer

B. DNA to RNA to protein

11-3 §11.MC source ↗

Which of the following is the enzyme that replaces the RNA nucleotides in a primer with DNA nucleotides?
  1. a.
    DNA polymerase III
  2. b.
    DNA polymerase I
  3. c.
    primase
  4. d.
    helicase

Answer

B. DNA polymerase I

11-4 §11.MC source ↗

Which of the following is not involved in the initiation of replication?
  1. a.
    ligase
  2. b.
    DNA gyrase
  3. c.
    single-stranded binding protein
  4. d.
    primase

Answer

A. ligase

11-5 §11.MC source ↗

Which of the following enzymes involved in DNA replication is unique to eukaryotes?
  1. a.
    helicase
  2. b.
    DNA polymerase
  3. c.
    ligase
  4. d.
    telomerase

Answer

D. telomerase

11-6 §11.MC source ↗

Which of the following would be synthesized using 5′-CAGTTCGGA-3′ as a template?
  1. a.
    3′-AGGCTTGAC-4′
  2. b.
    3′-TCCGAACTG-5′
  3. c.
    3′-GTCAAGCCT-5′
  4. d.
    3′-CAGTTCGGA-5′

Answer

C. 3′-GTCAAGCCT-5′

11-7 §11.MC source ↗

During which stage of bacterial transcription is the σ subunit of the RNA polymerase involved?
  1. a.
    initiation
  2. b.
    elongation
  3. c.
    termination
  4. d.
    splicing

Answer

A. initiation

11-8 §11.MC source ↗

Which of the following components is involved in the initiation of transcription?
  1. a.
    primer
  2. b.
    origin
  3. c.
    promoter
  4. d.
    start codon

Answer

C. promoter

11-9 §11.MC source ↗

Which of the following is not a function of the 5’ cap or 3’ poly-A tail of a mature eukaryotic mRNA molecule?
  1. a.
    to facilitate splicing
  2. b.
    to prevent mRNA degradation
  3. c.
    to aid export of the mature transcript to the cytoplasm
  4. d.
    to aid ribosome binding to the transcript

Answer

A. to facilitate splicing

11-10 §11.MC source ↗

Mature mRNA from a eukaryote would contain each of these features except which of the following?
  1. a.
    exon-encoded RNA
  2. b.
    intron-encoded RNA
  3. c.
    5’ cap
  4. d.
    3’ poly-A tail

Answer

B. intron-encoded RNA

11-11 §11.MC source ↗

Which of the following is the name of the three-base sequence in the mRNA that binds to a tRNA molecule?
  1. a.
    P site
  2. b.
    codon
  3. c.
    anticodon
  4. d.
    CCA binding site

Answer

B. codon

11-12 §11.MC source ↗

Which component is the last to join the initiation complex during the initiation of translation?
  1. a.
    the mRNA molecule
  2. b.
    the small ribosomal subunit
  3. c.
    the large ribosomal subunit
  4. d.
    the initiator tRNA

Answer

C. the large ribosomal subunit

11-13 §11.MC source ↗

During elongation in translation, to which ribosomal site does an incoming charged tRNA molecule bind?
  1. a.
    A site
  2. b.
    P site
  3. c.
    E site
  4. d.
    B site

Answer

A. A site

11-14 §11.MC source ↗

Which of the following is the amino acid that appears at the N-terminus of all newly translated prokaryotic and eukaryotic polypeptides?
  1. a.
    tryptophan
  2. b.
    methionine
  3. c.
    selenocysteine
  4. d.
    glycine

Answer

B. methionine

11-15 §11.MC source ↗

When the ribosome reaches a nonsense codon, which of the following occurs?
  1. a.
    a methionine is incorporated
  2. b.
    the polypeptide is released
  3. c.
    a peptide bond forms
  4. d.
    the A site binds to a charged tRNA

Answer

B. the polypeptide is released

11-16 §11.MC source ↗

Which of the following is a change in the sequence that leads to formation of a stop codon?
  1. a.
    missense mutation
  2. b.
    nonsense mutation
  3. c.
    silent mutation
  4. d.
    deletion mutation

Answer

B. nonsense mutation

11-17 §11.MC source ↗

The formation of pyrimidine dimers results from which of the following?
  1. a.
    spontaneous errors by DNA polymerase
  2. b.
    exposure to gamma radiation
  3. c.
    exposure to ultraviolet radiation
  4. d.
    exposure to intercalating agents

Answer

C. exposure to ultraviolet radiation

11-18 §11.MC source ↗

Which of the following is an example of a frameshift mutation?
  1. a.
    a deletion of a codon
  2. b.
    missense mutation
  3. c.
    silent mutation
  4. d.
    deletion of one nucleotide

Answer

D. deletion of one nucleotide

11-19 §11.MC source ↗

Which of the following is the type of DNA repair in which thymine dimers are directly broken down by the enzyme photolyase?
  1. a.
    direct repair
  2. b.
    nucleotide excision repair
  3. c.
    mismatch repair
  4. d.
    proofreading

Answer

A. direct repair

11-20 §11.MC source ↗

Which of the following regarding the Ames test is true?
  1. a.
    It is used to identify newly formed auxotrophic mutants.
  2. b.
    It is used to identify mutants with restored biosynthetic activity.
  3. c.
    It is used to identify spontaneous mutants.
  4. d.
    It is used to identify mutants lacking photoreactivation activity.

Answer

B. It is used to identify mutants with restored biosynthetic activity.

11-21 §11.MC source ↗

Which is the mechanism by which improper excision of a prophage from a bacterial chromosome results in packaging of bacterial genes near the integration site into a phage head?
  1. a.
    conjugation
  2. b.
    generalized transduction
  3. c.
    specialized transduction
  4. d.
    transformation

Answer

C. specialized transduction

11-22 §11.MC source ↗

Which of the following refers to the uptake of naked DNA from the surrounding environment?
  1. a.
    conjugation
  2. b.
    generalized transduction
  3. c.
    specialized transduction
  4. d.
    transformation

Answer

D. transformation

11-23 §11.MC source ↗

The F plasmid is involved in which of the following processes?
  1. a.
    conjugation
  2. b.
    transduction
  3. c.
    transposition
  4. d.
    transformation

Answer

A. conjugation

11-24 §11.MC source ↗

Which of the following refers to the mechanism of horizontal gene transfer naturally responsible for the spread of antibiotic resistance genes within a bacterial population?
  1. a.
    conjugation
  2. b.
    generalized transduction
  3. c.
    specialized transduction
  4. d.
    transformation

Answer

A. conjugation

11-25 §11.MC source ↗

An operon of genes encoding enzymes in a biosynthetic pathway is likely to be which of the following?
  1. a.
    inducible
  2. b.
    repressible
  3. c.
    constitutive
  4. d.
    monocistronic

Answer

B. repressible

11-26 §11.MC source ↗

An operon encoding genes that are transcribed and translated continuously to provide the cell with constant intermediate levels of the protein products is said to be which of the following?
  1. a.
    repressible
  2. b.
    inducible
  3. c.
    constitutive
  4. d.
    activated

Answer

C. constitutive

11-27 §11.MC source ↗

Which of the following conditions leads to maximal expression of the lac operon?
  1. a.
    lactose present, glucose absent
  2. b.
    lactose present, glucose present
  3. c.
    lactose absent, glucose absent
  4. d.
    lactose absent, glucose present

Answer

A. lactose present, glucose absent

11-28 §11.MC source ↗

Which of the following is a type of regulation of gene expression unique to eukaryotes?
  1. a.
    attenuation
  2. b.
    use of alternate σ factor
  3. c.
    chemical modification of histones
  4. d.
    alarmones

Answer

C. chemical modification of histones

11-34 §11.FITB source ↗

The process of making an RNA copy of a gene is called ________.

Answer

transcription

11-35 §11.FITB source ↗

A cell’s ________ remains constant whereas its phenotype changes in response to environmental influences.

Answer

genotype or genome

11-36 §11.FITB source ↗

The enzyme responsible for relaxing supercoiled DNA to allow for the initiation of replication is called ________.

Answer

DNA gyrase or topoisomerase II

11-37 §11.FITB source ↗

Unidirectional replication of a circular DNA molecule like a plasmid that involves nicking one DNA strand and displacing it while synthesizing a new strand is called ________.

Answer

rolling circle replication

11-38 §11.FITB source ↗

A ________ mRNA is one that codes for multiple polypeptides.

Answer

polycistronic

11-39 §11.FITB source ↗

The protein complex responsible for removing intron-encoded RNA sequences from primary transcripts in eukaryotes is called the ________.

Answer

Spliceosome

11-40 §11.FITB source ↗

The third position within a codon, in which changes often result in the incorporation of the same amino acid into the growing polypeptide, is called the ________.

Answer

wobble position

11-41 §11.FITB source ↗

The enzyme that adds an amino acid to a tRNA molecule is called ________.

Answer

aminoacyl-tRNA synthetase

11-42 §11.FITB source ↗

A chemical mutagen that is structurally similar to a nucleotide but has different base-pairing rules is called a ________.

Answer

nucleoside analog

11-43 §11.FITB source ↗

The enzyme used in light repair to split thymine dimers is called ________.

Answer

photolyase

11-44 §11.FITB source ↗

The phenotype of an organism that is most commonly observed in nature is called the ________.

Answer

wild type

11-45 §11.FITB source ↗

A small DNA molecule that has the ability to independently excise from one location in a larger DNA molecule and integrate into the DNA elsewhere is called a ________.

Answer

transposon or transposable element

11-46 §11.FITB source ↗

________ is a group of mechanisms that allow for the introduction of genetic material from one organism to another organism within the same generation.

Answer

Horizontal gene transfer

11-47 §11.FITB source ↗

The DNA sequence, to which repressors may bind, that lies between the promoter and the first structural gene is called the ________.

Answer

operator

11-48 §11.FITB source ↗

The prevention of expression of operons encoding substrate use pathways for substrates other than glucose when glucose is present is called _______.

Answer

catabolite repression

11-29 §11.TF source ↗

Cells are always producing proteins from every gene they possess.

Answer

False

11-30 §11.TF source ↗

More primers are used in lagging strand synthesis than in leading strand synthesis.

Answer

True

11-31 §11.TF source ↗

Each codon within the genetic code encodes a different amino acid.

Answer

False

11-32 §11.TF source ↗

Carcinogens are typically mutagenic.

Answer

True

11-33 §11.TF source ↗

Asexually reproducing organisms lack mechanisms for generating genetic diversity within a population.

Answer

False

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Problems and answers are adapted from Microbiology by Nina Parker, Mark Schneegurt, Anh-Hue Thi Tu, Philip Lister and Brian M. Forster, OpenStax, and are used under the CC BY-NC-SA 4.0 licence. Access for free at https://openstax.org/books/microbiology/pages/1-introduction. Illustrations: Copyright Rice University, OpenStax, under CC BY-NC-SA 4.0 license. This adaptation is released under the same licence, is non-commercial, and is neither affiliated with nor endorsed by OpenStax or Rice University.