Deck 23: Mutations and Repair

Question 1

Nonsense mutations occur when is introduced into the coding sequence of a gene.

A)a start codon
B)a stop codon
C)a deletion
D)an insertion

Answer 1

B

Question 2

In some repair mechanisms,the parental DNA strand is used as a guide for repairing mistakes made in the newly synthesized DNA strand.The cell is able to distinguish the parental strand from the new strand because immediately following replication,the DNA is .

A)fully methylated
B)still single-stranded
C)hemi-methylated
D)non-methylated

Answer 2

C

Question 3

A mutation that changes the orientation of a segment of DNA is called aan).

A)inversion
B)tranversion
C)reversion
D)frameshift

Answer 3

A

Question 4

DNA polymerases often proofread their recently inserted nucleotides.

Question 5

A mutation has no effect on phenotype.

A)frameshift
B)deletion
C)silent
D)nonsense

Question 6

Spontaneous mutations occur .

A)from errors in replication
B)when organisms grow at high temperatures
C)in the presence of mutagens
D)from ultraviolet radiation

Question 7

Which of the following is notorious for causing covalent bonding of adjacent thymine residues in DNA?

A)X-rays
B)infrared radiation
C)nucleotide analogs
D)ultraviolet radiation

Question 8

Mutations occur more frequently in hotspots.

Question 9

Terotogenic agents .

A)generate reversions
B)always causes mutations
C)are always carcinogenic
D)have known effects on developing embryos

Question 10

A mutation changes the coding sequence of the gene by inserting or deleting a single base pair.

A)nonsense
B)silent
C)frameshift
D)reversion

Question 11

When second site mutations change the mutant phenotype back to the wild type,this is called .

A)inversion
B)reversion
C)nonsense mutation
D)transversion