Unit Three Review Questions Flashcards
a process of dna transfer into a recipient cell that requires bacteriophage packaging is called ______
transduction
all of the following processes require a step of dna recombination to integrate the incoming dna into the host chromosomes except
a. transfer of a multidrug resistance plasmid
b. generalized transduction
c. specialized transduction
d. transposition of a mobile genetic element
a
the reason bacteria makes restriction endonucleases is _________
to prevent replication of an invading bacteriophage
which statement does not describe a process by which life forms actually change?
a. mutation accumulate at random, even in populations under the same selection pressure
b. natural selection favors the prevalence of traits with a fitness advantage in a given environment
c. when a pathogen associates with a host, the pathogen undergoes reductive evolution, losing the genes that specify the functions provided by the host
d. genetically distant organisms emerge from environments, and they prevail over preexisting organisms
d
which property is required for a molecule clock gene?
the gene must acquire mutations at a steady rate over time in all organisms compared
of the given genera, which genus is most distantly related to Escherichia coli ?
vibrio
supposed a pathogen bacterium acquires a plasmid expressing an enzyme that modifies the target of an antibiotic. which is most likely to happen when the antibiotic disappears?
the number of bacteria containing the resistance plasmid will decline because replicating the plasmid costs energy
which statement does not describe an example of reductive (degenerative) evaluation?
a. Treponema pallidum, the causative agent of syphilis, has lost many of the genes that encode enzymes for amino acid biosynthesis
b. T. pallidum has evolved virulence genes that enable it to take advantage of host cells
c. Wolbachia bacteria that live within host insect cells lack genes for biosynthesis of vitamins.
d. Chlamydia bacteria are obligate intracellular pathogens that fail to synthesize a peptidoglycan cell wall
b
when drug-resistant bacteria are isolated from a hospital patient, they may make smaller colonies than the original strain made. the reason is that _____
the random mutation that conferred resistance also conferred deleterious effects on growth
which statement best describes an example of bioinformatics analysis to reveal the capabilities of a pathogen?
a. Streptococcus pneumoniae was cultured on various agar media containing different combinations of nutrients in order to analyze the bacterium’s metabolism
b. S. pneumoniae was cultured with bacteriophage in order to transfer genes between bacteria
c. S. pneumoniae isolates were selected for genome analysis, which revealed the gene functions that were shared and the ones that were distinct to di!erent species
d. novel isolates of S. pneumoniae were constructed by genetic engineering
c
which statement best describes a result of gene duplication within a gene?
two genes within an organism’s genome show very similar dna sequences, but they encode enzymes that act on different substrates
which statement best describes evidence of highly divergent or distantly related organisms?
two genomes show very different proportions of gc versus at content
pathogen identification in a clinical laboratory is most commonly based on ______
a combination of dna-based tests and phenotypic traits
what are the basic ways microorganisms exchange dna?
