Microbiology, 2021

462 11 • Review Questions
24. 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?
A. conjugation
B. generalized transduction
C. specialized transduction
D. transformation
25. An operon of genes encoding enzymes in a
biosynthetic pathway is likely to be which of the
following?
A. inducible
B. repressible
C. constitutive
D. monocistronic
26. 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?
A. repressible
B. inducible
C. constitutive
D. activated
27. Which of the following conditions leads to
maximal expression of the lac operon?
A. lactose present, glucose absent
B. lactose present, glucose present
C. lactose absent, glucose absent
D. lactose absent, glucose present
28. Which of the following is a type of regulation of
gene expression unique to eukaryotes?
A. attenuation
B. use of alternate σ factor
C. chemical modification of histones
D. alarmones
True/False
29. Cells are always producing proteins from every
gene they possess.
30. More primers are used in lagging strand
synthesis than in leading strand synthesis.
31. Each codon within the genetic code encodes a
different amino acid.
Fill in the Blank
34. The process of making an RNA copy of a gene is
called ________.
35. A cell’s ________ remains constant whereas its
phenotype changes in response to
environmental influences.
36. The enzyme responsible for relaxing
supercoiled DNA to allow for the initiation of
replication is called ________.
37. 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 ________.
38. A ________ mRNA is one that codes for multiple
polypeptides.
39. The protein complex responsible for removing
intron-encoded RNA sequences from primary
transcripts in eukaryotes is called the
________.
32. Carcinogens are typically mutagenic.
33. Asexually reproducing organisms lack
mechanisms for generating genetic diversity
within a population.
40. 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 ________.
41. The enzyme that adds an amino acid to a tRNA
molecule is called ________.
42. A chemical mutagen that is structurally similar
to a nucleotide but has different base-pairing
rules is called a ________.
43. The enzyme used in light repair to split thymine
dimers is called ________.
44. The phenotype of an organism that is most
commonly observed in nature is called the
________.
45. 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 ________.
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