Chapter 9 (Part 2)

A __________ serves as the vector for transduction in bacteria

Bacteriophage

A bacterial cell escribed as __________ can accept soluble DNA from the surrounding environment.

Competent

R factors are specifically associated with which mechanism of recombination?

Conjugation

__________ in bacteria refers to horizontal gene exchange via pili.

Conjugation

Proteins that remove incorrect bases and replace them with correct ones are termed __________ repair enzymes.

Excision

In bacterial conjugation, a donor cell with a F (fertility) __________ located in the cytoplasm is considered F+.

Factor

In bacterial conjugation, a recipient cell having no F (fertility) __________ DNA is considered F-.

Factor

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: Mutations are always harmful to cells.

False

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

Frameshift

__________ mutations are generally most harmful to cells because they cause the greatest change in the amino acid sequence of a protein.

Frameshift

Which type of mutation is generally most harmful to cells?

Frameshift mutation

Plasmids are found in which type(s) of organisms?

Fungi, Bacteria

What type of DNA mutation occurs as a consequence of exposure to chemical or physical mutagens?

Induced

Which type of mutation results in a different amino acid begin incorporated into a protein?

Missense

Which is an agent that induces changes in DNA?

Mutagen

Which of the following defines a chemical or physical agent that introduces a change in DNA?

Mutagen

An organism that has a mutation is called a __________.

Mutant

A __________ mutation results in early termination of the protein.

Nonsense

Which mutation changes in amino acid producing codon into a stop codon?

Nonsense

What is the result of a point mutation that changes a template gene sequence from 3'-TACGCCATATAT-5' TO 3'-TACCGCCATCTAT-5'?

Nonsense mutation

Which process repairs DNA that has been damaged by ultraviolet radiation using visible light?

Photoactivation

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

Pilus

Gram-positive cells conjugate and transfer genetic material through which structure?

Pore in cell wall.

The main effect of ultraviolet radiation on DNA is abnormal bonding between adjacent __________.

Pyrimidines

Which type of plasmids confer the ability of an organism to survive treatment by antibiotics?

R factors

__________ refers to the transfer of genes between donor and recipient microorganisms.

Recombination

Which type of mutation is due to random mistakes in replication?

Spontaneous mutation

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.

What is the purpose of the Ames test?

To determine the carcinogenic potential of a chemical.

__________ involves the transfer of DNA via bacteriophages.

Transduction

Griffith's experiment using Streptococcus pneumoniae demonstrated the process of __________.

Transformation

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

Transformation

"Jumping genes" are known as __________.

Transposons

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

True

The native or __________ type strain describes cells that carry nonmutated DNA.

Wild

Gram-__________ cells conjugate and transfer genetic material through pores in their cell walls instead of pili.

Positive

In bacterial conjugation, F+ donor cells are high frequency recombinant (Hfr) cells when the __________ is integrated into the chromosomes.

Plasmid

True or false: point mutation results from an insertion or deletion of nucleotides, and always leads to a shift of the triplet sequence from the point of mutation downstream.

False: a frameshift mutation involves a shift of the triplet sequence from the point of mutation downstream. A mutation may also just include a substitution of bases, not a shift in the reading frame.

A __________ is a small circular segment of DNA found in the cytoplasm of bacteria that is capable of independent replication and usually contains nonessential genes.

Plasmid

Mutations that involve the addition, deletion or substitution of a single base are referred to as __________ mutations.

Point