Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Genetics > G1 > Flashcards

G1 Flashcards

You may prefer our related Brainscape-certified flashcards:
Biology 101 flashcards
1
Q

what is a silent mutation

and a synonomous mutation

A

triplet encodes the same AA

syn = codon specifies different but functionally equivalent

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what could mutation in intron cause

A

including in exon,

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what could mutation in promoter cause

A

over/under expression

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what are the 3 mechanisms that mutagens act through?

A

replacing a base
altering a base
damaging a base

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what kind of mutagens induce base replacement

A

base analogue
chemical analogue of natural bases
incorperated into dna in place of normal base can cause errors in replication and high rate of tautomeric shift

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what is tautomeric shift

A

base present in one of several forms (isomers)

taumeric shift is the sponatenous isomerisation of a nitrogen base to an alternative hydrogen bonding form

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what is the normal tautomeric form in DNA bases

A

keto form

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what happens if you get imino form of cytosine

A

pairs with adenine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what happens if ou get imino for of adenine

A

pairs with cytosine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what happens if you get the enol form of thymine

A

pairs with guanine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what happens if you get the enol for of guanine

A

pairs with thymine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what is 5- bromo uracil

A

in keto form is a thymine analogue contains bromine at C5 instead of CH3

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what does 5-bromouracil do in dna

A

in keto form still pairs to adenine
however presence of bromine modifies electron distributtion of ring, can be enol form or ionised form
which pairs with guanine
= promotes transitions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what effect does nitrous acid (HNO2) have on the bases

A

promotes oxidative deamination converting NH2 amino groups to keto groups
cytosine ->uracil (pairs A)
Adenine -> hypoxanthine (pairs c)
Guanine -> Xanthine (pairs C)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what type of organism does nitrous acid work best in

A

prokaryotes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what do alkylating agents do

A

cause specific mispairing

17
Q

what type of organism do alkylating agenets work best in

A

both pro and euk works well

18
Q

what are two common alkylating agents

A

EMS and NMG

ethylmethanesulfonate and nitrosoguanidine

19
Q

what is the most mutagenic wavelength of UV

A

254nm

20
Q

what does UV light do to DNA

- what are the knock on effects of this

A

cause dimers between adjacent pyrimidines
TT or TC dimers distorting double helix and interfereing wiith replication
the wrong base can then be inserted opposite them causing a missense/nonsense mutations
= premutational lesion

21
Q

What is human xeroderma pigmetosum

A

a autosomal recessive disease that is caused by a defect in excision repair of pyrimidine dimers

22
Q

What is the SOS system in E.coli

A

last resort damage tolerance that allows cells to survive with a degree of mutagenesis

23
Q

describe the SOS system in E.coli

A

UmuC or UmuD genes (which encode subunits of DNAPV)
code for error prone polymerases
DNAP3 stops at a non coding lesion (eg photodimer)
generating ss regions that attract Ssb protein and Rec A which form filaments
presence of RecA filaments signals cells to synthesize UmuD which is cleaved by RecA to yield UmuD adn UmuC
UmuC forms a complex with UmuD allowing DNAP to proceed past the lesion.

24
Q

what eukaryotes have been found to code for error prone polymerases as in SOS

A

yeast

25
Q

What are the most common types of radiation

A

Gamma rays
cobalt 60
or xrays

26
Q

what does the number of mutations caused by ionizing radiation depend on?

A

directly proportional to the dose recieved

27
Q

shorter the wavelength of radiation=

A

higher the energy and penetrating power

28
Q

what does ionizing radiation cause?

A

a trail of ions giving rise to free radicals in tissues which made ss and ds breaks in DNA
reaction products are OH- O2-, H202 as 65% of body in water.

29
Q

what are the most prevelent resulting mutations from radiation

A

thhymine glycol

8-oxo-7-hydrodeoxyguanosine

30
Q

what are intercalating agents

A

acridine dyes such as proflavin and acridine orange= flat/planar molecules that mimic base pair and slips between stacked nitrogen bases and DNA

31
Q

what effect do intercalating agents have on DNA

A

induce frameshit mutations leading to incorperation of an additional base on the opposite strand
as they increase spacing from 3-4A to 6A causing indel of bp at replication.

32
Q

what is the Ames test for mutagenicty

A

uses bacteria to test whether a given chemical cna cause mutations in DNA
positive test = mutation
induces reversion of various his mutations in bacterium S.thyphimutium

33
Q

what are the two most likely photoproducts from UV light?

A

cyclobutane pyrimidine photodimer

6-4- photoproducts

Genetics (22 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions