Exam 14: Microbial Genetics Mechanisms of Genetic Variation

Alternate forms of genes resulting from mutations are called

A __________ mutation does not alter the amino acid sequence of the resulting protein.

Site-specific recombination systems

Photoreactivation repairs thymine dimers by splitting them back into separate thymines.

A reciprocal exchange in which a pair of DNA with the same nucleotide sequence break and rejoin in a crossover is called __________ recombination.

Which one of the following contributes to the utility of the strains of Salmonella typhimurium used in the Ames reversion assay?

In an HFR $\times$ F⁺ mating, the conjugation bridge usually breaks before chromosomal transfer is complete. Therefore, the recipient remains F^-.

In order to take up a naked DNA molecule, a cell must be __________, which may occur only at certain stages in the life cycle of the organism.

Which of the following is true of the integration of a viral genome into the host chromosome?

The Ames test

Which of the following occurs with generalized transduction?

A mutagen that inserts between the stacked bases of a DNA double helix, distorting the DNA to induce single-pair insertions or deletions is called a(n) __________ agent.

Spontaneous mutations are caused by

__________ mutations affect only a single base pair in a gene.

In an F⁺ $\times$ F^- mating, all or part of the host chromosome usually is transferred to the recipient.

__________ __________ is the process by which some cells are capable of degrading an exogenote.

Which of the following best represents the order of gene transfer in an Hfr $\times$ F^- mating?

DNA molecules that enter a bacterium by one of several mechanisms is called a(n)

Which of the following effects may be mediated by transposable elements?

A plasmid that can either exist independently of the chromosome or be integrated into it is called a(n) __________.