microbiology exam 3

Conjugation between bacterial species has led to the development of strains that are

resistant to many antibiotics

The three methods of gene transfer in bacteria are

conjugation, transformation, transduction

During conjugation, the donor cell generally retains a copy of the genetic material being transferred. This is termed a

conservative process

DNA repair enzymes have as their substrate

damaged DNA

Vertical gene transfer

Transfer of DNA from parent organisms during reproduction

Which gene transfer method involves the uptake of free DNA by competent bacterial cells?

Transformation

Which of the following are characterized by their ability to move from one genomic location to another, including from one site in the chromosome to another site on the same chromosome?

Transposable elements

Genes encoding resistance to antimicrobial drugs can spread to different strains, species, and even genera, most commonly through conjugative transfer of

R, Plasmids

Which recombination method involves transfer of DNA via bacteriophages?

Transduction

Horizontal gene transfer

Transfer of DNA from a source other than the parent organisms

True or false: A mutation is an alteration in the DNA sequence or content of a cell that is passed on when the cell divides.

True

True or false: Mutations are always harmful to cells.

False

Which of the following is a type of mutation that affects only a single base pair in DNA?

Point

How do an Hfr cell and an F+ cell differ?

The plasmid is integrated into the chromosome of an Hfr cell but not in an F+ cell.

DNA damage can be resolved by

enzymes

A spontaneous mutation arises in DNA from

errors in DNA replication

A small number of __are considered beneficial in that they provide the cell with a useful change in structure or physiology. Antibiotic resistance in bacteria is an example.

mutations

A particular part of the host genome is included in the virus during___ transduction

specialized

Mutations that occur because of errors in DNA replication are termed

spontaneous

Bacterial cells that can accept soluble DNA from the surrounding environment are referred to as

Competent

In the Ames test, you expose S. typhimurium cells that cannot synthesize histidine to compound X, then plate them on a medium lacking histidine. The next day you observe a higher number of colonies on this plate versus the control plate, which has bacteria with no exposure. What reasonable conclusion can you draw?

Compound X is a mutagen.

Which of the following are methods of gene transfer in bacteria?

Conjugation Transformation Transduction

An insertion element consists of which two genetic elements?

DNA encoding enzymes for transposition tandem repeats

True or false: A cell with an integrated F factor transmits its genes at lower frequency than does a cell with a free plasmid in the cytoplasm.

False

True or false: In bacterial conjugation, all F+ donor cells are high frequency recombinant (Hfr) cells.

False

True or false: Plasmids are insertion sequences that can lead to changes in genotype within a cell or between cells.

False

Random fragments of host DNA are taken up by the bacteriophage during assembly in

Generalized

Which of the following are areas of the genome where multiple genes exist that are coordinated to create a new trait, making the bacterium more pathogenic?

Pathogenicity islands

In bacterial conjugation, which type of donor has the fertility factor integrated into the chromosome?

Hfr

Plasmids that encode resistance to a variety of antimicrobial agents and heavy metals are called Blank______ plasmids or factors.

R

A compound is subjected to the Ames test to evaluate its ability to cause mutation. If the substance is a mutagen, what results are expected?

There will be more bacterial colonies on the plate exposed to the mutagen than on the control plate.

Antibiotic resistant strains such as penicillin-resistant Neisseria gonorrhoeae have become more common in recent years due to

conjugation

Donor and recipient bacterial cells are connected by the pilus during

conjugation

During conjugation, the two bacterial cells are connected by the conjugative

pilus

A mutation that affects only a single base pair in DNA is termed a(n) mutation.

point

Transposable elements are capable of moving from

the chromosome to a plasmid a plasmid to the chromosome one site in the chromosome to another site in the chromosome

The method of DNA recombination in bacteria that involves the transfer of DNA via bacteriophages is called

transduction

The uptake of free DNA by competent bacterial cells occurs during bacterial

transformation

An insertion element is a type of

transposon

Insertion sequences that can lead to changes in genotype within a cell or between cells are called "jumping genes" or

transposons

True or false: A bacterial cell described as competent can accept soluble DNA from the surrounding environment.

true