module part 4

Question 1

caused by mutagens that damage DNA or alter its chemistry

Answer 1

induced mutations

Question 2

How can mutagens be classified?

Answer 2

Base analogs
Alkylating agents
Deaminating agents
Intercalating agents
Other mutagens

Question 3

structurally similar to normal nitrogenous bases and can be incorporated into DNA during replication; exhibit base-pairing properties

Answer 3

Base analogs

Question 4

change the base structure by adding alkyl group thereby altering its pairing characteristics causing mispairing

Answer 4

alkylating agents

Question 5

become inserted between the stacked bases of the helix, distort the DNA, and thus induce single nucleotide pair insertions or deletion that can lead to frameshifts

Answer 5

intercalating agents

Question 6

can severely damage DNA so that it cannot act as a replication template

Answer 6

other mutagens

Question 7

causes the formation of pyrimidine dimers

Answer 7

UV light

Question 8

causes base deletions, single-stand nicks, cross-linking and chromosomal breaks

Answer 8

ionizing radiations

Question 9

would be lethal without the repair mechanisms to restore DNA; however, the repair mechanisms are error prone, which also leads to mutations

Answer 9

other mutagens

Question 10

What are the different expression of mutations?

Answer 10

Forward mutation
reversion
point mutations

Question 11

conversion from the most prevalent gene form (wild type) to a mutant form

Answer 11

forward mutation

Question 12

second mutation that makes the mutant appear to be a wild type

Answer 12

Reversion

Question 13

What are the different types of Reversion?

Answer 13

back mutation
suppressor mutation

Question 14

conversion of the mutant nucleotide sequence back to the wild type sequence

Answer 14

back mutation

Question 15

reestablishment of the wild type phenotype by a second mutation that overcomes the effect of the first mutation; can be in the same gene or a different gene, but does not restore the original sequence

Answer 15

suppressor mutation

Question 16

affect only one base pair and are more common than large deletions or insertions;

Answer 16

point mutations

Question 17

different point mutations

Answer 17

silent mutations
missense mutations
nonsense mutations
frameshift mutations

Question 18

alterations of the base pair that do not alter the amino acid sequence of the protein because of code degeneracy

Answer 18

silent mutations

Question 19

alterations of the base sequence that result in the incorporation of a different amino acid in the protein

Answer 19

missense mutation

Question 20

What is the effect of missense mutation at the level of protein function?

Answer 20

complete loss of activity to no change in activity

Question 21

alterations that produce a translation termination codon, which results in premature termination of the protein during synthesis

Answer 21

nonsense mutation

Question 22

In what mutation does the location of the mutation within the protein will determine the extent of change in function?

Answer 22

Nonsense mutation

Question 23

insertions or deletions of one or two base pairs that thereby alter the reading frame

Answer 23

frameshift mutation

Question 24

Mutations can also occur in ______ sequences and in _______ and _____ genes; all can give observable phenotypes

Answer 24

regulatory; tRNA, rRNA