Gene Mutations and DNA Repair

Question 1

What is the source of all genetic variability

Answer 1

mutation

Question 2

What is a mutation

Answer 2

a heritable change in the sequence of an organisms genetic material that may alter phenotype

Question 3

What is a mutant

Answer 3

an organism that carries one or more mutations in genetic material

Question 4

_________________ _________________ best preserves the combinations best adapted to the existing environment = evolution!

Answer 4

natural selection

Question 5

What are somatic mutations

Answer 5

occur in somatic cells - occurs only in the descendants of that cell and will not be passed to progeny (not sex cells)

Question 6

What are germinal mutations

Answer 6

occur in germ-line cells and will be transmitted through gametes to progeny

Question 7

What are the two types of base substitution mutations

Answer 7

transitions and transversions

Question 8

What are the two types of insertion/deletion mutations

Answer 8

frameshift mutations and in-frame insertions and deletions

Question 9

What is a transition mutation

Answer 9

replaces a pyrimidine with another pyrimidine or a purine with another purine

Question 10

What is a transversion mutation

Answer 10

replaces a pyrimidine with a purine or a purine with a pyrimidine

Question 11

What is a frameshift mutation

Answer 11

when one OR two base pairs are inserted or deleted and alter the reading frame of the gene distal to the mutation

Question 12

What is a tautomeric shift

Answer 12

movement of H atoms from one position in a purine or pyrimidine base to another (change from enol to keto formation or for example)

Question 13

What can be generated through tautomeric shifts

Answer 13

rare A:C or G:T pairs during DNA replication

Question 14

In what generation do tautomeric shifts cause mutations

Answer 14

the second generation progeny

Question 15

What are expanding nucleotide repeats

Answer 15

expansion of triplet repeats

Question 16

Why is expanding nucleotide repeats considered a dynamic mutation

Answer 16

because with each round of replication, the repeat copy number is in flux

Question 17

What is a forward mutation

Answer 17

wild type to mutant

Question 18

What is a reverse mutation

Answer 18

mutant to wild type

Question 19

What is a missense mutation

Answer 19

amino acid to different amino acid

Question 20

What is a nonsense mutation

Answer 20

sense codon to a nonsense codon

Question 21

What is a silent mutation

Answer 21

codon to a different but equivalent codon

Question 22

What is a neutral mutation

Answer 22

amino acid change with no observable change in protein function

Question 23

What is a loss of function mutation

Answer 23

causes complete or partial loss of protein function

Question 24

What is a gain of function mutation

Answer 24

result of a mutation that causes the cell to produce a protein or gene product who’s function is not normally present

Question 25

What is a conditional mutation

Answer 25

expressed under only certain conditions

Question 26

What is a lethal mutation

Answer 26

causes premature cell death

Question 27

What is a suppressor mutation

Answer 27

a second site mutation that hides or supresses the effect of the first mutation

Question 28

What is an intragenic suppressor

Answer 28

a supressor mutation that occurs in the same gene

Question 29

What is an intergenic suppressor

Answer 29

a supressor mutation that occurs in a different gene

Question 30

Why are reverse mutations and suppressor mutations not the same thing

Answer 30

reverse: restores a wild type gene and phenotype
supressor: occurs at a site different from the mutation, and produces an individual with both the mutate and wild type genotype, but presents the wild type phenotype

Question 31

Are spontaneous mutations in genes common

Answer 31

no, however some regions of DNA have known hot spots for mutation