Microbiology Chapter 8: Bacterial Genetics

Competent

Cells that have the ability to take up DNA from the environment are called ________ cells.

Frameshift mutations Base substitutions

Chemical mutagens can cause what? (2 answers)

the plasmid DNA is integrated into the chromosome in these cells.

Chromosomal DNA is transferred with F plasmid DNA in an HFr cell because ___________.

transducing

In generalized transduction, donor DNA is mistakenly packaged into a phage coat, forming a _______ particle.

False; conjugation in bacteria refers to asexual gene exchange between two bacteria via a structure called a pilus.

True or false: Bacterial conjugation does not require contact between the two cells.

silent mutation nonsense mutation nonsense mutation

Which of the following are possible outcomes of a base substitution? silent mutation nonsense mutation thymine dimer mutation silent mutation nonsense mutation frameshift mutation

Chromosomal DNA Plasmid DNA

Which of the following can be transferred from one cell to another by conjugation? Bacterial RNA Bacterial proteins Chromosomal DNA Plasmid DNA

frameshift

Which type of mutation alters the reading frame of a gene?

Single stranded breaks Double stranded breaks Nucleobase alterations

X rays can cause which types of damage to a DNA molecule?

reversion

________ is the change of a mutated genetic sequence back to its original, non-mutated form.

bacteria

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

Replication and transcription

Thymine dimers can kill cells if left unrepaired, as they cause kinks in DNA that interfere with the process of _______ and __________.

R

Protection against the toxic effects of antimicrobial compounds or heavy metals is often found to be encoded on ________ plasmids.

spontaneous

Random genetic changes that occur as a result of natural cellular processes are called _______ mutations.

A restriction enzyme that recognizes and cuts at a short nucleotide sequence A modification enzyme that adds protective methyl groups to the cell's own DNA

Restriction-modification systems of bacteria include what two components?

Transcription and replication

The distortion of DNA by thymine dimers directly blocks which cellular processes?

genetic, genotype

The general mechanisms by which most bacteria routinely respond to new circumstances are __________ change and regulating __________ expression.

substitution

The most common type of mutation is the base _______, where an incorrect nucleotide is incorporated during DNA replication.

transduction

The transfer of bacterial DNA from a donor to recipient via a bacteriophage is called _________.

intercalating

__________ agents insert themselves between adjacent base pairs in a DNA strand, increasing the rate of frameshift mutations.

transposons

"Jumping genes," or ________, can lead to changes in genotype within a cell or between cells.

nonsense

A ________ mutation is a base substitution that changes an amino acid encoding codon to a stop codon.

DNA or RNA genome Protein coat

A bacteriophage consists of what two major components?

auxotroph

A mutant that requires a growth factor is a(n) ____________.

Horizontal gene transfer mutation

Genetic change in bacteria occurs through which two mechanisms?

By adding methyl groups to the nucleobases of the cell's DNA that are recognized by the restriction enzyme

How does a modification enzyme protect a bacterial cell from its own restriction enzyme?

wild

If a scientist is working with bacteria that have the typical phenotype of those isolated from nature, the bacteria are considered to be _________ type.

core

In E. coli, about 75% of the genes are found in all strains. These conserved genes are called the ___________ genome.

is integrated into the chromosome

In bacterial conjugation, F+ donor cells are high frequency recombinant (Hfr) cells when the F plasmid __________.

genomic island

A(n) _________ _______ is a large segment of a cell's genome that has clearly originated in a different species.

frameshift

A(n) __________ mutation results from an insertion or deletion of nucleotides, leading to a shift of the reading frame from the point of mutation downstream.

analogs

Base ________ structurally resemble nucleobases and can be mistakenly incorporated into nucleotides and then into DNA.

pilus

Donor and recipient bacterial cells are connected by a sex ______ during conjugation

transcriptional

Most transposons contain ______ terminators.

donor cell DNA

A transducing particle carries _______.

False; Although both types of donors have plasmid DNA, only the Hfr cell has the plasmid integrated into the chromosome

True or False: In bacterial conjugation, all F* donor cells are high frequency recombination (Hfr).

transposases gene inverted repeats antibiotic resistance gene

What are components of the simplest transposon, an insertion sequence?

Restriction-modification CRISPR

What are the systems that bacteria can use to protect against invading DNA?

mutagen

What is an agent that induces changes in DNA?

F prime

When an excision error produces a plasmid containing both chromosomal and F plasmid DNA, the resulting plasmid is called a(n) __________ plasmid.

transposons

Mutagens that are DNA segments that insert themselves into genes and inactivate them are called ________.

base-pairing

Mutagens that modify nucelobases change their ________ - ________ properties.

within that cell before being released

When bacteriophages replicate, phage components are synthesized in the host cell and assemble into new viruses ___________.

Lysed bacterial cells Secreted into the environment by bacteria

Which of the following are sources of "naked" DNA? Lysed bacterial cells Secreted into the environment by bacteria Contained within bacteria that lack cell walls Contained in bacteriophages

Natural selection

_________ __________ is the process by which organisms better adapted to an environment reproduce at a higher rate