Question 1

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

Accepted Answer

A) They are highly permeable to test substances. 
B) They are defective in DNA repair and,therefore,cannot readily repair damage done by the test substances. 
C) It is very straightforward to assay the conversion of their histidine auxotrophy mutations to histidine prototrophy. 
D) All of the choices are correct. 
A) They are highly permeable to test substances. 
B) They are defective in DNA repair and,therefore,cannot readily repair damage done by the test substances. 
C) It is very straightforward to assay the conversion of their histidine auxotrophy mutations to histidine prototrophy. 
D) All of the choices are correct.

Question 2

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.

Accepted Answer

The answer of In order to take up a naked...

Question 3

Transition mutations can result from

Accepted Answer

A) incorporation of a base analog that exhibits different base-pairing properties from the base it replaces. 
B) chemical modification of an existing base in the DNA so that in the next round of replication it will pair differently from the unmodified base. 
C) incorporation of a base analog that exhibits different base-pairing properties from the base it replaces and chemical modification of an existing base in the DNA so that in the next round of replication it will pair differently from the unmodified base. 
D) a small insertion or deletion. 
A) incorporation of a base analog that exhibits different base-pairing properties from the base it replaces. 
B) chemical modification of an existing base in the DNA so that in the next round of replication it will pair differently from the unmodified base. 
C) incorporation of a base analog that exhibits different base-pairing properties from the base it replaces and chemical modification of an existing base in the DNA so that in the next round of replication it will pair differently from the unmodified base. 
D) a small insertion or deletion.

Question 4

Which of the following conclusions can be made if two identical insertion sequences are identified in separate locations on a chromosome?

Accepted Answer

A) The insertion sequence was transferred via replicative transposition. 
B) The insertion sequence was a "cut-and-paste" transposon. 
C) The insertion sequence was transferred via simple transposition. 
D) A mutation occurred during transposition of the insertion sequence. 
A) The insertion sequence was transferred via replicative transposition. 
B) The insertion sequence was a "cut-and-paste" transposon. 
C) The insertion sequence was transferred via simple transposition. 
D) A mutation occurred during transposition of the insertion sequence.

Question 5

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.

Accepted Answer

A) insertional 
B) interspersing 
C) intercalating 
D) distortional 
A) insertional 
B) interspersing 
C) intercalating 
D) distortional

Question 6

A __________ is a piece of extrachromosomal DNA that has its own replication origin.

Accepted Answer

The answer of A __________ is a piece of extrachromosomal...

Question 7

Mutations resulting from exposure to physical or chemical agents are called __________ mutations.

Accepted Answer

The answer of Mutations resulting from exposure to physical or...

Question 8

A cell that is Hfr and a cell that is F+ can be the same cell.

Accepted Answer

A) True 
 B)False

Question 9

Which of the following mutagens is most different than the others in terms of its effect on DNA?

Accepted Answer

A) Acridine orange 
B) Intercalating agent 
C) Planar mutagen that inserts between stacked bases 
D) Base analogue 
A) Acridine orange 
B) Intercalating agent 
C) Planar mutagen that inserts between stacked bases 
D) Base analogue

Question 10

Approximately half of known animal carcinogens can be detected by the Ames test.

Accepted Answer

A) True 
 B)False

Question 11

An F' plasmid results when

Accepted Answer

A) an F+ /F- mating is interrupted before completion. 
B) an Hfr * F- mating is interrupted before completion. 
C) an integrated F plasmid is incorrectly excised,bringing host genes with it. 
D) None of the choices are correct. 
A) an F+ /F- mating is interrupted before completion. 
B) an Hfr * F- mating is interrupted before completion. 
C) an integrated F plasmid is incorrectly excised,bringing host genes with it. 
D) None of the choices are correct.

Exam 16: Mechanisms of Genetic Variation

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

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.

Transition mutations can result from

Which of the following conclusions can be made if two identical insertion sequences are identified in separate locations on a chromosome?

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.

A __________ is a piece of extrachromosomal DNA that has its own replication origin.

Mutations resulting from exposure to physical or chemical agents are called __________ mutations.

A cell that is Hfr and a cell that is F+ can be the same cell.

Which of the following mutagens is most different than the others in terms of its effect on DNA?

Approximately half of known animal carcinogens can be detected by the Ames test.

An F' plasmid results when

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A cell that is Hfr and a cell that is F⁺ can be the same cell.