Unit 6

Question 1

Mutations

Answer 1

random and heritable changes in the sequence of DNA that can no longer be repaired

Question 2

Types of mutation lesions

Answer 2

Abasic sites
Base mismatches
modified bases
Inter/intra strand crosslinks
double strand breaks

Question 3

Point mutations

Answer 3

single base pair changes anywhere in the DNA sequence

Question 4

Types of point mutations

Answer 4

Base substitutions
Base deletion
Base insertion

Question 5

Types of base substitutions

Answer 5

Transition - purine for purine or pyrimidine for pyrimidine
transversion - purine replaced with pyrimidine or pyrimidine replaced with purine

Question 6

Silent mutations

Answer 6

new codon encodes for same amino acid

Question 7

Missense mutation

Answer 7

new codon codes to different amino acid

Question 8

Nonsense mutation

Answer 8

changes a coding codon to a stop codon

Question 9

Frameshift mutation

Answer 9

removal or addition of base pairs disrupts the triplet reading frame

Question 10

Mutations are _____ and ______

Answer 10

spontaneous and random

Question 11

Spontaneous mutations arise by:

Answer 11

errors in DNA replication/recombination
DNA damage
Insertion of transposons

Question 12

Slippage

Answer 12

mispairing between template and synthesized strand in regions with repetitive sequences

Question 13

Most common way mutations are introduced to DNA

Answer 13

mispairing of nucleotides

Question 14

What does tautomerization of nucleotides lead to?

Answer 14

purine-pyrimidine mismatches and transition mutations

Question 15

Klenow fragment

Answer 15

DNA polymerase proofreading

Question 16

What does ionization of nucleotides lead to?

Answer 16

purine-pyrimidine mismatches

Question 17

depurination

Answer 17

lose of purine base because of hydrolysis of the sugar/base bound

Question 18

deamination

Answer 18

removal of amine group from C, A, and G by hydrolysis

Question 19

when does DNA damage become a mutation

Answer 19

a DNA lesion is not corrected by endogenous repair mechanisms

Question 20

mutagen

Answer 20

a chemical or physical force that can increase the mutation rate

Question 21

What can mutagens do

Answer 21

replace base pair in DNA strand
chemically alter base pair leading to mismatch
damage a base pair so it cant pair with other nucleotides

Question 22

Types of mutations (origin and frequency)

Answer 22

Spontaneous
Induced

Question 23

Spontaneous mutation

Answer 23

mistakes during replication

Question 24

Induced mutation

Answer 24

caused via known chemical and physical agents