mutations mod32

Question 1

What are tautomer shifts

Answer 1

when the protons shift forming a rare form so a base analog

Question 2

What is the rare imino base pairing

Answer 2

A:C

Question 3

what is the rare enol base pairing

Answer 3

G:T

Question 4

what is the effect of mismatched base pairs for rare imino

Answer 4

A:C base pairing results in C:G base pair sub

Question 5

What is the effect of mismatched base pairs for rare enol

Answer 5

G:T base pairing results in T:A base pair

Question 6

what factors influence the rate of spontaneous mutations

Answer 6

accuracy of the dna replication

efficiency of dna repair

Question 7

what are the 2 types of chemical mutagens

Answer 7

Mutagenic to only replicating dna and mutagenic to both replicating and nonreplicating

Question 8

what are the chemicals that are mutagenic only to replicating DNA

Answer 8

Base analogs and Acridines

Question 9

what are the chemicals that are mutagenic to both replicating and non

Answer 9

Alkylating agents, deaminating agents and hydroxylating agents

Question 10

Name the 2 base analogs

Answer 10

5 bromouracil BU

2 Aminopurine AP

Question 11

name the acridine

Answer 11

Proflavin

Question 12

Name a deaminating agent

Answer 12

Nitrous Acid

Question 13

Name the hydroxylating agent

Answer 13

Hydroxylamine

Question 14

Base analogs increase the likelihood of what happening

Answer 14

Mispairing

Question 15

5 bromouracil is an analog of what base

Answer 15

Thymine

Question 16

structure of 5 bromouracil

Answer 16

Br at position 5 instead of CH3

Question 17

Br increases frequency of what

Answer 17

Tautomeric shifts

Question 18

what does the following forms of 5BU pair with

1) stable keto form
2) instable enol form

Answer 18

1) pairs A

2) pairs G

Question 19

What is the mutagenic effect of 5BU

Answer 19

Transition

Question 20

When 5BU is present in its less frequent enol form, what happens

Answer 20

Induces G:C –> A:T

Question 21

When 5BU is present in its common keto form, what happens

Answer 21

A:T –> G:C

Question 22

Acridine dyes like proflavin cause what

Answer 22

Frameshift mutations

Question 23

Proflavin affects the double helix in what way and how?

Answer 23

increases rigidity and alters conformation because proflavin gets in between the base pairs in DNA

Question 24

What do alkylating agents do

Answer 24

add alkyl groups to base CH3

Question 25

What do deaminating agents do

Answer 25

Remove NH2 from bases

Question 26

Hydroxylamine does what

Answer 26

hydroxylates the amino group of cytosine and leads to G:C –> A:T transitions

Question 27

Hydroxylamine is useful in classifying what

Answer 27

transition mutations

Question 28

For lung cancer, what genes are mutated

Answer 28

Several anti cancer genes and chromosomes

Question 29

How do Xrays and UV light induce mutations

Answer 29

Xrays - through ionisation

UV - through excitation (non ionizing radiation)

Question 30

X rays can specifically mutate how

Answer 30

Breaks chromosomes, cause deletions, duplication, inversions and translocations

Question 31

The increased what of atoms present in DNA is responsible for most mutagenicity ( Radiation)

Answer 31

The increased reactivity of atoms present in DNA molecules is responsible for most of the mutagenicity

Question 32

what are the products of DNA that has absorbed UV radiation

Answer 32

Pyrimidine hydrates and pyrimidine dimers

Question 33

what is a pyrimidine hydrate

Answer 33

UV + H20 = extra OH on the base

Question 34

What is pyrmidine dimer

Answer 34

Two pyrimidine joined together

Question 35

hydrolysis of cytosine to a hydrate causes what

Answer 35

mispairing during replicaton

Question 36

Thymine dimers do what

Answer 36

block DNA replication and activate error-prone DNA repair mechanisms

Question 37

UV can be used beneficially how

Answer 37

used to sterilise surface by inducing formation of thymine dimers which block dna replication