quiz 7: ch 8

A _______ mutation results from an assertion or deletion of nucleotides, leading to a shift of the reading fame from a point of mutation downstream

frameshift

a ____ ____ is a large segment of a cell's genome and clearly originates in different species

genomic island

during transduction, donor DNA is injected into a recipient cell by a phage. This DNA integrates into the recipient's chromosome by

homologous recombination

the bacterial conjugation, F' donor cells are high frequency recombinant (Hfr) cells when the F plasmid _______

is integrated into the chromosome

genetic change in bacteria occurs through what two mechanisms:

mutation, horizontal gene transfer

a base substitution that changes an amino acid-encoding codon to a stop codon is called a(n) ______ mutation

nonsense

genomic islands that encode disease-causing factors such as endotoxins, capsules, and adherence factors are Called ______ islands

pathogenicity

the _____ is the observed characteristic of an organism

phenotype

______ are circular pieces of bacterial DNA that do not usually encode information essential to life of a cell

plasmids

the return of a gene from a mutated state to its original, non-mutated state is called a ______

reversion

random genetic changes that result from normal cellular processes are_______

spontaneous mutations

base _______ mutations occur when an incorrect nucleotide is incorporated in place of another during DNA synthesis

substitution

chromosomal DNA is transferred with F plasmid DNA in an Hfr cell because ______

the plasmid DNA is integrated into the chromosome in these cells

DNA-mediated ______ involves the uptake of "naked" DNA by competent bacterial recipient cells

transformation

variation in color of corn kettles was due to _____ elements

transposable

"jumping genes" or _____, can lead to changes in genotype within a cell or between cells

transposons

sequences of DNA that can move to new positions within the genome of a single cell are called

transposons

bacteriophages can consist of

-DNA genome -RNA genome -protein coat (capsid)

possible outcomes of a base substitution

-nonsense mutation -silent mutation -missense mutation

components of the simplest transposon, an insertion sequence?

-transposase gene -inverted repeats

Genomic Island

Large genomic segment in a cell's genome that originated in another species

DNA-Mediated Transformation

Mechanism of horizontal gene transfer in which "naked" DNA is taken up by the recipient cell.

Transduction

Mechanism of horizontal gene transfer in which bacterial DNA is transferred inside a phage coat.

Conjugation

Mechanism of horizontal gene transfer in which the donor cell physically contacts the recipient cell.

Phage DNA

Phage genome that sometimes carries additional genes

Homologous Recombination

Process by which a cell replaces a stretch of DNA with a segment that has a similar nucleotide sequence.

Plasmid

Replicon that is independent of the chromosome and generally encodes only non-essential genetic information

Transposon

Segment of DNA that can move from one site to another in a cell's genome.

Transposon

Segment of DNA that directs its own movement to another location in chromosomal or plasmid DNA

X rays

action: Cause single- and double-strand breaks in DNA result: Deletions

Intercalating agents

action: Insert between base pairs, pushing them apart result: Addition or subtraction of nucleotides

Transposons

action: Randomly insert into DNA result: Insertional inactivation

Ultraviolet (UV) light

action:Causes thymine dimers to form result: Errors during repair process

a _______ is a virus that infects bacteria, and can transfer bacterial genes from a donor cell to a recipient cell

bacteriophage

a bacterial cell described as _______ can take up DNA from the surrounding environment

competent

when bacteriophages replicate, phage components are synthesized in the host cell and assemble into new viruses ______

within that cell before being released

the common consequence of a ______ mutation is the appearance of an early stop codon that produces a shortened and thus non-functional protein

frameshift

the type of transduction that can transfer any genes of a host cell is called _______ transduction

generalized

once donor DNA is in a recipient cell, it integrates into that cell's chromosome by ______

homologous recombination

Plasmid

A DNA molecule that replicates independently of the chromosome.

Mutation

A change in the nucleotide sequence of a cell's DNA that is passed on to daughter cells.

Prototroph

A microorganism that does not require any organic growth factors.

Auxotroph

A microorganism that requires an organic growth factor.

Non-Homologous Recombination

DNA recombination that does not require extensive nucleotide sequence similarity in the stretches that recombine.

Horizontal Gene Transfer

DNA transfer from one bacterium to another by conjugation, DNA-mediated transformation, or transduction.

when an excision errors produces a plasmid containing both chromosomal and F plasmid DNA, the resulting plasmid is called a(n) _____ plasmid

F'

bacteria routinely adapt to new circumstances by ______

-regulating gene expression -genetic change

Phenotype

The observed characteristics of a cell.

Genotype

The sequence of nucleotides in an organism's DNA.

Vertical Gene Transfer

Transfer of genes from parent to offspring.

Base analogs

action: Base-pairing properties differ from those of nucleobases normally found in DNA result: Nucleotide substitution

Chemicals that modify nucleobases

action: Chemical modifications change base-pairing properties of nucleobases result: Nucleotide substitution

________ are an excellent model system for genetics studies because they can quickly grow to high densities, allowing us to screen for rare genetic events

bacteria

during ______ recombination, a segment of DNA inserts into the cell's genome, a process that does not quite require a similar nucleotide sequence in the region of recombination

non-homologous

the base substitution mutation leading to a stop codon is an example of a ______ mutation

nonsense

consider a population of bacteria susceptible to an antimicrobial. if a bacterium acquires a spontaneous mutation that gives resistance to the antimicrobial, this bacterium will ________ if the population is exposed to the antimicrobial

grow without competition