Chapter 8 micro quizlet – Flashcards
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The designation his- refers to
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the genotype of a bacterium that lacks a functional gene for histidine synthesis AND bacteria that are auxotrophic for histidine.
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Segments of DNA capable of moving from one area in the DNA to another are called
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transposons
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Transposons
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are informally known as jumping genes.
may cause insertion mutations.
may cause knockout mutations.
were first recognized in plants.
All of the choices are correct.
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Chemical mutagens often act by altering the
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hydrogen bonding properties of the nucleobase.
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The largest group of chemical mutagens consists of
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alkylating agents
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Nitrous acid most frequently causes mutations by
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converting cytosine to uracil
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Chemical mutagens that mimic the naturally occurring bases are called
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base analogs
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Planar molecules used as chemical mutagens are called
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intercalating agents
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Intercalating agents
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act during DNA synthesis AND often result in frame shift mutations.
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Irradiation of cells with ultraviolet light may cause
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thymine dimers
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Thymine dimers are dealt with by
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photoreactivation repair AND excision repair.
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The formation of a covalent bond between two adjacent thymines is caused by
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UV radiation
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X-rays
.
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cause single and double strand breaks in DNA molecules.
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DNA repair mechanisms occur
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in both eukaryotes and prokaryotes.
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Which is not true about mismatch repair?
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It removes both strands in the mismatch area.
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Antibiotics
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provide an environment in which pre-existing mutants survive.
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Prokaryotic cell mutations can be observed very quickly because the prokaryotic chromosome is
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haploid
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The diploid character of eukaryotic cells may mask the appearance of a mutation since
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the matching chromosome may carry the dominant gene.
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Direct selection involves inoculating cells onto growth media on which
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the mutant but not the parental cell type will grow.
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A clever technique that streamlines the identification of auxotrophic mutants is
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replica plating
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To increase the proportion of mutants in a population of bacteria one may use
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penicillin enrichment
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A quick microbiological test for potential carcinogens was developed by
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Ames
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To increase the chance of detecting carcinogens in the Ames Test, the test substance is treated with
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ground up rat liver
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The Ames test is useful as a rapid screening test to identify those compounds that
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are mutagens
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Bacteria that have properties of both the donor and recipient cells are the result of.
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genetic recombination
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The mechanism by which genes are transferred into bacteria via viruses is called
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transduction
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In conjugation the donor cell is recognized by the presence of
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an F plasmid
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Competent cells
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are able to take up naked DNA, occur naturally AND can be created in the laboratory.
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The material responsible for transformation was shown to be DNA by
.
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Avery, MacLeod and McCarty.
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In conjugation, transformation, or transduction, the recipient bacteria is most likely to accept donor DNA.
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from the same species of bacteria.
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Gene transfer that requires cell-to-cell contact is
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conjugation
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Insertion sequences
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are the simplest type of transposon, code for a transposase enzyme AND are characterized by an inverted repeat.
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The transfer of vancomycin resistance from Enterococcus faecalis to Staphylococcus aureus is thought to have involved
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conjugation AND transposons
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Which is not true about a crown gall tumor?
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It is a bacterial infection of plants.
It requires a plasmid.
It produces a large amount of opines that neither the plant nor bacteria synthesizes.
It is due to the incorporation of bacterial plasmid DNA into the plant chromosome.
All of the choices are true
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The study of the crown gall tumor found
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a bacterial plasmid promoter that was similar to plant promoters.
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Organisms termed his- are considered prototrophic for histidine.
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False
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Each gene mutates at a characteristic frequency.
True
False
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True
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DNA polymerase is able to proofread the DNA sequence.
True
False
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True
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The Ames test determines antibiotic sensitivity of a bacterium.
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False
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False
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Double-stranded DNA enters the recipient cell during transformation.
True
False
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False
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Plasmids often carry the information for antibiotic resistance.
True
False
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True
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F plasmids and oftentimes R plasmids are both able to code for production of a pilus.
True
False
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True
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Transposons may leave a cell by incorporating themselves into a plasmid.
True
False
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True
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Crown gall is caused by a prokaryote plasmid that can be expressed in plant cells.
True
False
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True
