Chapter 19: Gene Mutation and DNA Repair

Question 1

Mutation

Answer 1

a permanent change in the genetic material that can be passed from cell to cell or from parent to offspring

Question 2

Point mutation

Answer 2

change in a single base pair within DNA sequence

Question 3

Base Substitution

Answer 3

point mutation in which one base is substituted for another

Question 4

Transition

Answer 4

point mutation involving a change of pyrimidine to another pyrimidine (e.g., C to T) or a purine to another purine (e.g., A to G)

Question 5

Transversion

Answer 5

point mutation in which a purine is interchanged with a pyridine, or vice versa

Question 6

Deletion/Addition

Answer 6

Short sequence of base pairs is deleted or added from DNA

Question 7

Silent Mutation

Answer 7

A mutation that does not alter the amino acid sequence of the encodes polypeptide even though the nucleotide sequence has changed

Question 8

Missense Mutation

Answer 8

a base substitution that leads to a change in the amino acid sequence of the encoded polypeptide

Question 9

Nonsense Mutation

Answer 9

a mutation that involves a change from a sense codon to a stop codon

Question 10

Frameshift Mutation

Answer 10

a mutation that involves the addition or deletion of nucleotides not in a multiple of three and thereby shifts the reading frame of the codon sequenced downstream form the mutation

Question 11

Apart from silent mutations, new mutation are more likely to produce polypeptides with….

Answer 11

reduced function rather than enhanced

Question 12

Missense mutations are less likely to alter function because…..

Answer 12

they only involve change in one AA in the polypeptide

Question 13

Neutral mutation

Answer 13

a mutation that has no detectable effect on protein function or no detectable effect on the phenotype of the organism. (this is seen with silent mutations and missense most often)

Question 14

Mutations can occasionally result in enhanced function, but it is rare

Answer 14

• may result in greater “fitness”
  *natural selection would favor this
  *increase in frequency in a population

Question 15

Gene mutations can also be defined by their effect on _____________ genotype and phenotype

Answer 15

wild-type

Question 16

wild-type is the allele that is

Answer 16

most common in the population

Question 17

mutant allele is a

Answer 17

change tot the wild-type

Question 18

Reversion is when mutant allele is

Answer 18

changed back to wild-type

Question 19

Mutants are characterized by

Answer 19

their ability to survive

Question 20

Deleterious mutation

Answer 20

a mutation that has a detrimental effect on phenotype

Question 21

Lethal mutation

Answer 21

mutation that produces an allele that causes the death of a cell or organism

Question 22

Beneficial mutation

Answer 22

a mutation that has a beneficial effect on phenotype

Question 23

Conditional mutants

Answer 23

a mutant whose phenotype depends on the environmental conditions, such as temp, sensitive mutants

Question 24

Mutations may occur in

Answer 24

germ-line (cells that give rise to gametes) or somatic cells

Question 25

Germ-line mutation

Answer 25

a mutation in a cell of the germ line

Question 26

Somatic mutation

Answer 26

a mutation in a somatic cell

Question 27

genetic mosaic

Answer 27

individuals that has a somatic regions that differ genotypical from each other