Lecture Quiz Questions Flashcards
(31 cards)
What type of procedure is appropriate to isolate revertants from a population of threonine autotrophic cells?
Grow the autotrophic cells on an agar plate without threonine; any colonies that form are presumed revertant.
_______ are strains that are unable to grow on a minimal medium that supports growth of the wild type strain, but are able to grow on the minimal medium if one or more nutritional supplements are added.
Autotrophs
The Ames test….
Can be used to measure the mutagenicity of chemicals.
The ______________ is the most prevalent form of a gene in a population.
Wild type
A microbial geneticist observes that a significant number of pyrimidine dimers are present in bacterial DNA following exposure to a particular mutagen. What mutagen was the cells likely exposed to?
UV light
A change in genotype, but not in phenotype, is most likely due to….
A point mutation in the third position of a DNA triplet.
Mutations that result in death of an organism when exposed are called…..
Lethal mutagens
A mutation form the most prevalent form of a gene to a mutant form is called a……
Forward mutagen
A __________ mutation does not alter the amino acid sequence of the resulting protein.
Silent
What is considered a reverse mutation that will restore the wild type phenotype?
True reversion back to the wild type base sequence.
Mutation to a different base sequence, but one that restores the amino acid sequence in the protein to the wild type sequence.
A mutation that restores the function of a protein even though it does not restore the base sequence or the amino acid sequence to the wild type.
During generalized transduction…..
The host chromosome is degraded into randomly sized fragments.
Any DNA fragment of the appropriate size is packaged.
Any bacterial gene may be transferred to the subsequent host.
Specialized transduction can be carried out by…..
Only those temperate bacteriophages that integrate into the host chromosome.
If chromosomal DNA from a host is the only type of DNA carried by a transducing particle, what can be concluded regarding transduction in this case?
Transduction in this case is generalized rather than specialized.
If the att site of E. Coli was dissimilar to that of lambda phage due to mutation, how would transduction be affected.w I e
Phage DNA would be unable to integrate into host DNA.
A microbiologist observes that all plates of bacteria B contain colonies that are fluorescent, while for bacteria A only the plates from stationary phase demonstrate fluorescent colonies. What can be concluded?
Both bacteria A and B cells are competent.
When an F’ plasmid acts as the donor in a mating, which of the following do(es) NOT happen?
Some chromosomal genes not on the plasmid are transferred.
Does happen
The recipient becomes F’
The plasmid is transferred, including the chromosomal genes now on the plasmid
When a recipient cell acquires a piece of naked DNA from the environment, it is called…..
Transformation
Which statement best summarizes the major distinction between horizontal gene transfer and vertical gene transfer?
The recipient of genes in horizontal transfer is a mature cell, whereas the recipient of genes in vertical transfer is a progeny cell.
When bacterial genes are transferred to another bacterium by a virus, it is called….
Transduction
Alternative forms of genes resulting from mutations are called….
Alleles
What is true of the actinomycetes?
They closely resemble the fungi in morphology.
Actinomycetes form….
Substrate mycelia and aerial mycelia.
The medically useful compounds some actinomycetes produce when forming aerial mycelia are called….
Secondary metabolites
Actinomycetes….
Form asexual spores.
