Chapter 11

Question 1

Mutations that occur in germ-line cells, giving rise to sperm and egg, are called __________

Answer 1

germ-line mutations

Question 2

Cells not in the germ line are called somatic cells; mutations in such cells are called _______

Answer 2

somatic mutations

Question 3

Germ-line mutations _______ be passed from one generation to the next, while only _______ descendants of the original mutated somatic cell will carry the mutation

Answer 3

can
direct

Question 4

localized mutations or _______ occur at a specific identifiable position in a gene

Answer 4

point mutation

Question 5

Genes with elevated mutation rates are called _______

Answer 5

mutation hot spots

Question 6

What are the 2 different types of base-pair substitution mutations?

Answer 6

1) transitions
2) transversions

Question 7

What substitution results in transitions?

Answer 7

A to G (vice versa)
C to T (vice versa)

Question 8

What are the 3 results that can result from a base pair substitution?

Answer 8

1) silent mutation
2) missense mutation
3) nonsense mutation

Question 9

_______: no amino acid change

Answer 9

silent mutation

Question 10

_______: changes in amino acid

Answer 10

missense mutation

Question 11

_______: creates a premature stop codon

Answer 11

nonsense mutation

Question 12

_______ or _______ of one or more base pairs altering the reading frame of the message

Answer 12

insertion or deletion

Question 13

insertion or deletion of one or more base pairs that alters the reading frame results in _______

Answer 13

frameshift mutations

Question 14

Mutations that alter consensus sequence nucleotides of promoters are called _______

Answer 14

promotor mutations

Question 15

promotor mutations interfere with the efficiency of _______

Answer 15

transcription initiation

Question 16

Mutations that alter mRNA required for specific sequences at either end of the intron are called _______

Answer 16

splicing mutations

Question 17

Base-pair substitutions that results in the production of new splice sites that replace or compete with authentic splice sites during mRNA processing are called _______

Answer 17

cryptic splice sites

Question 18

polyadenylation mutations can _______ proper 3’ processing of mRNA

Answer 18

block

Question 19

_______: converts a wild type allele to a mutant allele

Answer 19

forward mutation

Question 20

_______: convert mutant alleles to wild-type or near wild-type

Answer 20

reverse mutations or reversions

Question 21

_______: wild-type DNA sequence is restored by a second mutation within the SAME codon

Answer 21

true reversion

Question 22

_______ is reversion that occurs through mutation elsewhere in the same gene

Answer 22

intragenic reversion

Question 23

_______ occurs by a mutation in a different gene and together the two mutations restore the organism to wild-type

Answer 23

second-site reversion

Question 24

Second site reversions are also known as _______ because the second mutation “suppresses” the mutant phenotype caused by the first mutation

Answer 24

suppressor mutations

Question 25

_______ can arise in cells without exposure to agents capable of inducing mutations

Answer 25

spontaneous mutations

Question 26

Spontaneous mutations arise primarily through errors in _______ or spontaneous changes in the chemical structure of a _______

Answer 26

DNA replication
nucleotide base

Question 27

Alterations in the number of DNA repeats occur via _______; which results in a portion of the DNA forming a temporary hairpin

Answer 27

strand slippage

Question 28

_______ are a special class of mutations causing some hereditary diseases in humans and other organisms where increases in number of repeats beyond a certain threshold causes disorders

Answer 28

Trinucleotide repeat disorders

Question 29

_______: the loss of a purine from a nucleotide by breaking the covalent bond linking the nucleotide base to the sugar

Answer 29

Depurination

Question 30

The site where the loss of a purine occurs is called the _______ site

Answer 30

apurinic

Question 31

If left unrepaired, DNA polymerase will usually compensate by putting a(n) _______ into the site during replication

Answer 31

adenine

Question 32

_______: the loss of an amine group (NH2) form a nucleotide

Answer 32

deamination

Question 33

When a cytosine is deamninated, an oxygen atom usually takes its place, converting the cytosine into a _______

Answer 33

uracil

Question 34

When methylated cytosine is deaminated, a _______ base is produced

Answer 34

thymine

Question 35

Agents that cause DNA damage leading to mutation are called _______

Answer 35

mutagens

Question 36

_______ can fit between DNA base pairs and distort the DNA duplex

Answer 36

intercalating agents

Question 37

Intercalating agents lead to distortion that can lead to _______ resulting in added or lost nucleotides

Answer 37

DNA nicking

Question 38

_______ are aberrant structures with additional bonds involving nucleotides; caused by UV irradiation

Answer 38

photoproducts

Question 39

What are the 2 photoproducts?

Answer 39

1) Thymine dimer
2) 6-4 photoproduct
- both occur between thymines

Question 40

Radiation such as X-rays, Gamma rays, and radioactive materials can cause _______ or _______ breaks in DNA that block DNA replication

Answer 40

single-strand
double-strand