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genetics semester 1 > bacterial genetics > Flashcards

bacterial genetics Flashcards

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1
Q

polymorphism

A

cite in a gene sequence displaying variation in a population

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2
Q

hox genes

A

group of related genes controlling body plan of an embryo along a head-tail axis

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3
Q

scabrous

A

ethanol reward as memory aid insignalling pathway of long-term memory

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4
Q

hangover

A

ethanol tolerance aid as well as response to heat and oxidative stress

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5
Q

syntaxin

A

mutations affect ethanol tolerance to sedation, encoding synaptic vesicle release protein

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6
Q

simple/ single gene defect disease

A

Duchenne MD
huntington’s

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7
Q

complex/multi gene defect disease

A

Cancer
diabetes/obesity

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8
Q

wild type

A

unmodified isolate of a species, well-characterized in the lab

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9
Q

mutant

A

differs to wild-type in that changes to DNA sequence have occurred

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10
Q

mutation

A

specific change/changes to a DNA sequence different to the wild-type

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11
Q

phenotype

A

observable trait

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12
Q

genotype

A

nucleotide sequence of a region of DNA

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13
Q

why are bacteria used as genetic models?

A

much is known about them
easy to manipulate
short generation time

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14
Q

vertical gene transfer

A

changes in DNA passed on to progeny

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15
Q

horizontal gene transfer

A

changes to DNA passed on from other bacteria/viruses

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16
Q

genetic transformation scientists

A

Fred Griffith
- conversion of non-pathogenic strept. pneum into a pathogenic

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17
Q

conjugation scientists

A

Lederburg and Tatum
- 2 e coli strains mixed and progeny isolated with both characteristics

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18
Q

transduction scientists

A

Zinder and Lederburg
- displayed bacterial viruses carrying DNA from one bacterium to another

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19
Q

Bacterial transformation

A

ability of bacterial cell to uptake DNA from other cells in the same environment

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20
Q

Competence

A

correct physiological state for recipient cell in order to uptake DNA
naturally/ artificially induced

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21
Q

purpose of transformation

A

increase functional/ metabolic capabilities to compete in environment

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22
Q

bacterial conjugation

A

gene transfer via cell-to-cell contact mating

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23
Q

conjugation mediation

A

conjugative plasmid can induce pilus/ transfer DNA

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24
Q

high frequency recombination strains

A

can transfer part of host chromosome to recipient

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25
Q

mob genes

A

allow for genetic transformation of a non-conjugative bacterial cell

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26
Q

stages of bacterial conjugation

A

donor cell attaches to recipient cell via pilus
pilus contracts
1 plasmid DNA strand attaches
recip and donor cell synthesize complementary strands to form an F+ cell

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27
Q

bacterial transduction

A

gene transfer via bacterial virus mediation

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28
Q

transducing particle

A

phage filled wiyh host and chromosomal DNA

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29
Q

stages of transduction

A
  1. bacteriophage injects DNA
  2. phage enzymes degrade host DNA
  3. cell produces more phages incorporating host/ phage DNA
  4. transducing particles transform other cells as donor DNA incorporated into recipient chromosome via recombination
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30
Q

transcription

A

decoding genetic info enmcoded by DNA into RNA
1 step process

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31
Q

decoding genetic info to proteins

A

2 step process (transcription/translation

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32
Q

bacterial genetic decoding

A

transcription and translation coupled
genes of related function often clustered on chromosome

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33
Q

transcription mediator

A

RNA polymerase

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34
Q

transcription 3 stages

A

initiation, elongation, termination

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35
Q

types of rNTPs

A

rATP, rUTP, rCTP, rGTP

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36
Q

Inititiation

A

RNA polymerase attaches to promoter sequence in DNA

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37
Q

elongation

A

RNA polymerase moves along template strand, decoding to RNA

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38
Q

termination

A

RNA polymerase recognizes terminating sequence and finishes transcription prior to strand separation

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39
Q

1 residue

A

1 amino acid= 3 ribonucleotides= 1 codon

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40
Q

number of possible codons per amino acid

A

64

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41
Q

number of proteins potential depending on reading frame

A

3

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42
Q

number of reading frames

A

2 strands with 3 proteins each

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43
Q

how is choice of reading frame determined

A

an ATG/AUG start codon
- ribosome binding site in front is complementary to 3’ end of 16S rRNA

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44
Q

2 stages of bacterial DNA replication

A

binary fission
DNA synthesis

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45
Q

DNA polymerase action in bacterial DNA replication

A

creates phosphodiester linkage between 5’OH end of DNA and 3’PO4 end on dNTP

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46
Q

DNA synthesis precursors

A

deoxynucleoside triphospates
dATP dGTP dCTP dTTP

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47
Q

bacterial replication

A

begins at oriC before proceeding bidirectionally (creating 2 replication forks) and finishing at terminus C (terC)

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48
Q

6 types of mutation

A

base-pair changes
deletions
inversions
insertions
frame-shifts
duplications

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49
Q

2 types of base-pair change mutations

A

transition/ transversion

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50
Q

base pair transition

A

pyrimidine> pyrimidine/ purine> purine

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51
Q

base pair transversion

A

pyrimidine<>purine

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52
Q

3 potential consequences of base-pair mutations

A

silent mutation (same sequence)
missense mutation (different sequence)
nonsense mutation (stop codon)

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53
Q

mutation frequency formula

A

m/N
no. mutants/ no. bacteria

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54
Q

mutant selection

A

general selection
1. isolate randomly distributed mutants
2. screen

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55
Q

specific selection

A

every isolated mutant of interest screened

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56
Q

negative selection

A

selects against muatnt growth

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57
Q

enrichment

A

negative selection use to promote growth of mutants and inhibiting wild-type/ competition growth w antibiotic

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58
Q

positive selection

A

selective conditions to promote mutant growth
(usually in resistance to a phage)

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59
Q

genomics

A

acquisition, storage, retrieval and analysis of DNA sequence

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60
Q

genome size range
(most common?)

A

0.13-14MBp
most common =3 MBp

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61
Q

E.Coli model strain
characteristics?

A

K12 strain
rapid growth, simple nutritional requirements

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62
Q

K12 relatives

A

meningitis
UTI
gastroenteritis
typhoid
plague

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63
Q

E.Coli chromosome size

A

4.6MBp

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64
Q

streptomyces coelicolor chromosome

A

linear chr

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65
Q

parts of streptomyces coelicolor chromosome

A

core (maintenance genes)
arms (variable extras)

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66
Q

ARTEMIS

A

visualisation tool displaying annotation files graphically

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67
Q

metagenomics

A

study of genetic material recovered directly from environmental samples

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68
Q

recombinant DNA industries

A

food, pharma, agriculture, medical research

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69
Q

food recombinant DNA examples

A

chymosin (cheese manufacture)
golden rice (enzymes promoting B carotene synthesis)

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70
Q

pharma recombinant DNA examples

A

human insulin (pig replacement)
HGH (cadaver replacement)
blood clotting factor VIII (haemophilia)
Hep B vaccine (yeast cell production)

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71
Q

medical research recombinant DNA examples

A

HIV antibody test

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72
Q

agriculture recombinant DNA examples

A

proteins (herbicide resistance)
glyphosphate (herbicide round-up)

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73
Q

resources for recombinant DNA tech

A

enzymes, DNA/ RNA, vectors, cells

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74
Q

types of enzyme used in recombinant DNA tech

A

restriction
taq polymerase
ligase
reverse transcriptase

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75
Q

restriction enzymes

A

cleave DNA at specific sequences
often recognise palindromic 4-8 Bp

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76
Q

DNA ligase

A

anneals

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77
Q

taq polymerase

A

amplification of DNA fragments

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78
Q

reverse transcriptase

A

converts RNA back to DNA

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79
Q

2 types of cleavage pattern

A

symmetrical (blunt end production)
asymmetrical (sticky end production)

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80
Q

2 types of DNA in recombinant DNA tech

A

insert/ vector

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81
Q

vector DNA

A

unique restriction sites
efficient oriC
gene expression regulatory sequences

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82
Q

plasmid size

A

2-200 kbp

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83
Q

vectors for larger DNA fragments

A

bacteriophages
cosmids/phagemids

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84
Q

cosmids/ phagemids

A

genetically engineered hybrids replicating as plasmid and packaged as bacteriophage

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85
Q

clone production steps

A
  1. prepare insert/vector
  2. ligate both
  3. transform recomb DNA into host
  4. select hosts containing DNA
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86
Q

isolation of specific inserts

A

cleaved via restriction nuclease

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87
Q

amplification of non-specific insert

A

cDNA copies total mRNA and reverse transcriptase used

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88
Q

amplification of specific DNA

A

PCR

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89
Q

Steps in DNA insertion

A
  1. isolate insert from RNA/DNA
  2. ligate insert into vector
  3. transform into host cell
  4. select recomb DNA hosts
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90
Q

ligation of insert into vector

A

cleaving of plasmid and ligase annealing of insert

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91
Q

transformation into host cell

A
  1. plasmid mixed in
  2. heat shock and CaCl induces competence of cells
  3. taken up by plasmid and selectively cultured
  4. recomb purified and expressed
  5. expression in host
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92
Q

selection of recomb DNA hosts

A

selective medium growth

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93
Q

insertional inactivation

A

DNA fragment in polylinker disrupts lacZ gene > inactive b galactosidase > no blue pigment detected by X-gal

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94
Q

how to check for recombinant DNA

A

Hybridization of ssDNA to probe
screening for protein expression
PCR

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95
Q

E.coli requirement for expression in host

A

expression vector

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96
Q

expression vector mechanism

A

contains promoter sequence recognised by host RNA polymerase and therefore expressed gene ligated at 3’ end

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97
Q

direct expression of recombinant protein

A

purification
investigation of protein function

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98
Q

expression of modified version of protein

A

cloned gene engineered to : change protein properties/ investigate fine details of a protein

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99
Q

non-coding DNA

A

introns
exons

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100
Q

intron

A

nucleotide sequence within gene
removed via splicing during RNA maturation

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101
Q

exon

A

gene region produced after intron removal

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102
Q

when would inactive form be expressed

A

if genomic DNA ligated into expression vector

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103
Q

bacterial expression systems advantages

A

simple
cheap
short generation time
large yield

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104
Q

bacterial expression systems disadvantages

A

can fail to fold crrectly, losing bio activity
toxic proteins to bacterial cell
no post-trans modifications

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105
Q

yeast expression systems advantages

A

simple
cheap
resembles mammalian cells
quick
pos trans modifications

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106
Q

yeast expression systems disadvantages

A

protease containing (degrades recomb proteins)
differing post-trans modifications

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107
Q

insect cell expression systems advantages

A

cheaper than mammalian
high-level expression
correct folding
post-trans modifications

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108
Q

insect cell expression systems disadvantages

A

post-trans modifications differ from mammalian cells

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109
Q

mammalian expression systems advantages

A

best for mammalian
correct folding
post trans modifications

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110
Q

mammalian expression systems disadvantages

A

expensive
complex cells
grow to lesser densities

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111
Q

example of expression for commercial use

A

diabetes

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112
Q

example of protein expression for further research

A

HIV

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113
Q

where’s insulin produced

A

beta cells of islets of langherhan in pancreas

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114
Q

bovine/porcine insulin considerations

A

side-effects
ethics
purification issues
contamination issues

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115
Q

insulin structure

A

2 polypeptide chains linked by disulfide bonds

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116
Q

synthesis of insulin procedure

A

folding stabilized by disulfide bonds, connecting peptide removed

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117
Q

recombinant insulin production

A

proinsulin gene (2introns) coding for mRNA which is reverse transcribed to cDNA, inserted into a recombinant plasmid and transforms bacterium

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118
Q

genetic model organisms wanted characteristics

A

short lifespan
readily available
amenable to genetic transformation
large offspring yield
small;
rapid development rate

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119
Q

e.coli cell

A

gram-negative, rod-shaped bacterium

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120
Q

generation time of E.coli

A

20-30 mins

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121
Q

e coli advantages

A

simple
safe
short generation times

122
Q

e coli disadvantage as model organism

A

prokaryptic so differ to eukaryotic

123
Q

homologue

A

gene related to another gene via descent from a common ancestoral DNA sequence

124
Q

orthologue

A

genes from different species evolved from a common ancestral gene

125
Q

paralogue

A

genes generated by a duplication event

126
Q

gene knockout

A

gene sequences completely/ partially removed, inhibiting gene expression

127
Q

gene knockdown

A

techniques interfering/ reducing gene expression

128
Q

yeast budding/fission advantages

A

share characteristics of cell div cycle, gene expression, signalling pathways w humans
short life cycle
small
simple growth/ storage
easily transformable w plasmids
trivial construction of gene knockouts/ knockdowns

129
Q

drosophilia melanogaster advantages

A

small
easy to collect
2 week life cycle
14000 gene encoding
easy to cross
phenotypic markers
transformable
research useful

130
Q

p transposon

A

jumping gene used to transform drosophilia

131
Q

drosophilia research areas

A

cell signalling
development
neurological disease

132
Q

disease model

A

mutant model organism mimicking human phenotypes of disease

133
Q

spinal muscular atrophy

A

neurodenegerative disease decreasing motor function
caused by mutation in smn gene
flys hold orthologous smn gene

134
Q

alzheimers

A

accumulation of amaloid beta peptide
progressive neuron loss

135
Q

C. elegans

A

small, non-parasitic nematode
transparent
easy to manipulate
both sexes
300 offspring pp
2-3 week lifespan

136
Q

c. elegans dsRNA interference procedure

A
  1. dsRNA complementary to region of interest introduced
  2. process to short interfering siRNA’s
  3. prevtnion of expression of region of interest
137
Q

zebra fish

A

transparent embryos
200 eggs weekly
difficult to sequence etc
knockdown possible w morphilinos
micro-injectible

138
Q

zebra fish research areas

A

vertebrate development
neurobiology
toxicology
disease/ drug discovery

139
Q

mus musculus

A

closely related to humans
identical gene composition offspring (lab inbreeding)
embryonic manipulation
knockouts available

140
Q

mouse knockout process

A
  1. embryonic stem cells w one copy of target cell deleted
  2. injected into early embryo
  3. hybrid embryo introduced to mouse
  4. hybrid offspring
  5. further cycles > homozygous KO
141
Q

C value paradox

A

gene number doesn’t increase linearly with genome size

142
Q

percentage of human genome-wide repeats

A

44%

143
Q

G-banding

A

mild proteolyis then GIEMSA
AT rich

144
Q

R banding

A

heat denaturation then GIEMSA
GC rich

145
Q

Q banding

A

quinacrine stain
AT rich

146
Q

C-banding

A

BaOH then GIEMSA
Constitutive heterochromatin

147
Q

alpha satellite

A

large arrays of repeated sequences

148
Q

assembly site for kinetochore

A

centromere

149
Q

positioning of centromere

A

metacentric
submetacentric
arcocentric
telocentric

150
Q

short chr arms

A

p

151
Q

long chr arms

A

q

152
Q

telomere

A

specialised region at chr ends

153
Q

function of telomere

A

allows distinguishment between real chromosome end/ unnatural so that unnatural is destroyed
end replication problem

154
Q

end replication problem

A

3’ terminal isn’t copied > ssDNA overhang degraded
telomeres therefore prolong replicative senescence

155
Q

telomerase

A

recognizes uncopied region
adds multiple copies of ‘TTAGGG’ repeat
replication machinery synthesizes other strand

156
Q

histones

A

form octamer which DNA wraps to form nucleosome

157
Q

euchromatin

A

relatively uncondensed
associated w active genes

158
Q

heterochromatin

A

condensed
associated w silenced gene-poor regions

159
Q

B-chromosomes

A

additional chromosomes possessed by some in population

160
Q

holocentric

A

no singular cetromere, multiple kinetochores throughout

161
Q

kinetochore

A

protein structure located at centromere, serving as attachment point for mitotic spindles

162
Q

centriole

A

9 microtubule groups, generating mitotic spindle fibres

163
Q

G2 of interphase

A

chromosomes extended
chromatin duplicated

164
Q

chiasma

A

physical connection between 2 non-sister chromatids
leads to crossing over between pairs

165
Q

meiosis prophase 1

A

leptopene
zygotene
pachytene
diplotene
diakenesis

166
Q

synaptonemal complex

A

nucleoprotein zipper between paired homologous chromosomes
role in crossing over/ chiasma formation

167
Q

disjunction

A

1/2 of tetrad migrates to each pole

168
Q

oocytosis

A

begins in embryonic ovary and arrests in prophase 1

169
Q

nondisjunction

A

aneuploid gametes

170
Q

trisomy

A

3 copies of specific chromosome

171
Q

mitosis vs meiosis

A

meiosis is reductional division
cant occur in haploids
2 successive divisions
mitosis 1 division
occurs in haploids/ diploids

172
Q

sexual reproduction disadvantages

advantages

A

time and energy to find mate
potential breaking apart of favourable gene

better equipped for environmental changes

173
Q

2 hypotheses of sex determination

A

protenos mode
lygaeus mode

174
Q

heterogametic

A

producing unlikely gametes

175
Q

homogametic

A

producing uniform gametes

176
Q

klinefelter syndrome

A

tall with feminised physique
poor beard growth
low IQ
breast development
female pubic hair
testicular atrophy
osteoperosis
44 autosomes + XXY

177
Q

Turner syndrome

A

short
constricted aorta
elbow deformity
no menstruation
brown spots
44 autosomes + 1X

178
Q

human Y chromosome regions

A

PAR
SRY
MSY
PAR

179
Q

MSY regions

A

euchromatin
centromere
euchromatin
heterochromatin

180
Q

PAR

A

pseudoautosomal regions
sharing homology with X chromosome
synapse and recombine with x chromosome in meiosis

181
Q

MSY

A

Male Specific Region of Y
doesnt synapse w x chromosome

182
Q

SRY

A

sex determining region of Y
produces testes determining factor,triggers undifferentiated gonadal tissue of embryo to form testes

183
Q

dosage compensation

A

females likely produce twice as much gene product for all X-linked genes
> mechanism required to equate X-linked gene product doses

184
Q

Barr body

A

condensed X-chromatin
inactivated X chromosome

185
Q

barr body formation

A

dosage concentration supported by X chromosome inactivation

186
Q

lyonization

A

inactivation random at early point in development
once inactivated, all progeny cells have same X-chromosome inactivated

187
Q

anhidrotic ectodermal dysplasia

A

x-linked mutation causing sweat gland absence
males have no sweat glands
females have mosaic of D/d sections over body

188
Q

X chromosome inactivation mechanisms

A

initiated from XIC (X inactivation centre)
produces 2 non-coding RNA transcripts (Xist/ Tsix)
leads to packaging of 1 X chr into v dense, compacted form of chromatin

189
Q

polycistronic

A

mRNA corresponding to multiple genes whose expression is also controlled by single promoter/terminator

190
Q

prokaryotic promoter

A

sigma factor recognises sequence upstream of gene, positioning RNA polymerase

191
Q

holoenzyme

A

sigma factor + RNA polymerase

192
Q

no. of RNA polymerases in prokaryotes

A

1

193
Q

no. of RNA polymerases in eukaryotes

A

3
RNA polym 1, 2, 3

194
Q

RNA polym 1

A

ribosomal RNA

195
Q

RNA polym 2

A

all protein-coding genes

196
Q

RNA polym 3

A

non-coding RNA’s

197
Q

RNA polym 2 promoters in eukaryotes

A

TATA box bound by transcription factor IID complex, recruiting RNA polym 2 and txn factors
5’ cap added while RNA transcribed

198
Q

transcription termination

A

transcripts end 10-35nt downstream of signal AAUAAA
RNA cut via endonuclease, releasing DNA
poly(A) tail added

199
Q

prokaryotic gene expression alteration ways

A

alternative sigma factors (different -35/-10 sequences)

200
Q

how many sigma factors do E coli have

A

7

201
Q

mutation of sigma factor

A

affects expression of set of gene regulating

202
Q

eukaryotic various transcription factors

A

allows stimuli to affect each promoter

203
Q

microarray

A

DNA corresponding to each gene in sequence dotted onto slide

204
Q

mutation in intron

A

doesn’t affect coding sequence
could affect splicing

205
Q

mutation in exon

A

alters coding sequence

206
Q

intron/ exon boundaries function

A

define limits
recruit machinery removing introns from RNA (“spliceosome”)

207
Q

capping

A

1st modification made to RNA polym 2- transcribed RNA

208
Q

polyadenylation

A

addition of poly(A) tail to RNA transcript

209
Q

small ribosomal sub-unit

A

reading of mRNA

210
Q

large ribosomal sub-unit

A

houses synthetic petidyl transferase centre

211
Q

ribosome function

A

finds ORF start and interprets codons so as to pair w tRNA

212
Q

how does start codon recognition differ in pro/eu?

A

eukaryotic mRNA has a cap

213
Q

Shine-dalgarno sequence

A

large sub-unit binds to small sub-unit, translates/ initiates on downstream AUG

214
Q

continuous variation

A

e.g. height/ foot size
polygenic

215
Q

Mendel’s first law

A

2 copies of each gene segregate in meiosis

216
Q

Mendel’s second law

A

copies of each gene segregate independent of other genes in Meiosis

217
Q

when do Mendel’s laws not apply

A

when both alleles are found on same chromosome

218
Q

unlinked genes

A

meiosis independent assortment

219
Q

linked genes

A

can’t assort independently

220
Q

Hardy-weinberg formulae

A

p^2 + 2pq +q^2= 1

221
Q

Hardy Weinberg assumptions

A

infinitely large population
random mating
no evolutionary forces acting

222
Q

when does the Hardy-weinberg principle not work?

A

gene flow
genetic drift
non-random mating
natural selection

223
Q

examples of autosomal recessive conditions

A

albinism
cystic fibrosis
phenylketoneuria
sickle cell
haemochromatosis
tay-sachs

224
Q

phenylketoneuria

A

inability to metabolize phenylalanine

225
Q

Tay-sachs

A

neurodegeneration due to lack of N-acetyl-hexosaminidase

226
Q

cystic fibrosis

A

thick mucus build-up due to CFTR absence

227
Q

haemochromatosis

A

excess iron accumulation due to mutation in HFE gene of which there are 2 mutant alleles

228
Q

HFE gene

A

regulates hepcidin production

229
Q

hepcidin

A

iron regulatory hormone determining iron absorption from food/store release

230
Q

examples of autosomal dominant conditions

A

huntington’s
FASP
polycystic kidney disease
polydacyly
achondroplastic dwarfism
hypercholesterolaemia

231
Q

achondroplastic dwarfism

A

FGFR3 mutation
failure to convert cartilage to bone

232
Q

autosomal recessive pedigree

A

trait appears in progeny
horizontal pedigree pattern

233
Q

autosomal dominant pedigree

A

trait appears in every generation
vertical pediree pattern

234
Q

X-linked recessive disorders

A

haemophilia
muscular dystrophy

235
Q

haemophilia

A

absence of factor VIII
blood doesnt clot

236
Q

X-linked dominant disorders

A

hypophosphataemia

237
Q

hypophosphatemia

A

vit-D resistant rickets

238
Q

Leri-weill dyschondrosteosis

A

bone growth disorder
lack of SHOX gene copy

239
Q

co-dominance

A

traits show up equally in F1

240
Q

3 blood group alleles

A

I^a/I^b/i

241
Q

incomplete dominance

A

F1 resembles neither parent

242
Q

pleiotrophy

A

genes/alleles affecting more than one unrelated characteristic
e.g. manx phenotype

243
Q

epistasis

A

gene modifying/masking phenotype of another gene

244
Q

hypostatic

A

gene/allele being masked/modified

245
Q

penetrance

A

number of members in population of specific genotype displaying the expected phenotype

246
Q

expressivity

A

range of signs/symptoms that can occur in different people w genetic condition

247
Q

polydactyly

A

incomplete penetrance as variable digits of progeny

248
Q

complementation group

A

set of mutations mapping to same chromosomal locus, failing to complement when crossed

249
Q

how is complementation skewed?

A

intragenic complementation

250
Q

intragenic complementation

A

proteins w multiple functions forming multimers

251
Q

linkage

A

genes on same chromosome, co-segregating in crosses

252
Q

test-cross for 2 traits/genes

A
  1. construct double heterozygote
  2. cross w tester homozygous recessive for both traits
253
Q

recombination frequency

A

(no. recombinants/ total progeny) *100

254
Q

distance between 2 loci

A

1 centimorgan = 1 *10^6 Bp

255
Q

syntenic genes

A

grouped in same way on chromosomes of 2+ species

256
Q

synteny blocks

A

regions containing homologous genes

257
Q

translocation

A

where 2 non-homologous chromosomes break and exchange fragments

258
Q

acute myelogenous leukaemia

A

coding region for C-terminus of AML transcription replacement
required for haematopoiesis, coding region unrelated to other allele

259
Q

centric fusion

A

2 telocentric chr fuse / generate new chromosome

260
Q

robertsonian translocation

A

2 acrocentric p lost and 2q remaining fuse

261
Q

result of robertsonian translocation

A

down syndrome/ patau syndrome

262
Q

inversion

A

segment of chromosome becomes inverted with original position

263
Q

2 types of inversion

A

pericentric
paracetric

264
Q

paracentric

A

1 arm

265
Q

pericentric

A

2 arms

266
Q

result of chromosome inversions

A

small gene duplications/ large gene duplications prior to deletion of superfluous genes/ divergence of retained homologues

267
Q

unequal crossover

A

strandbreak resulting in unequal crossover/ different no. repeat units

268
Q

sister chromatid exchange

A

strandbreak on sister chromatids produces different repeat numbers

269
Q

transcription factors in eukarya

A

bind motifs in promoter, promoting/inhibiting RNA pol II ability to initiate transcription

270
Q

intron/ exon boundaries function

A

defines limits
recruit machinery removing introns from RNA

271
Q

purpose of alternative splicing

A

can yield multiple products from each gene

272
Q

bacterial translation

A

shine-dalgarno sequence recognised by small ribosomal subunit RNA via base-pairing
large binds to small sub-unit and translates downstream of AUG
small sub-unit binds CAP and large binds to first AUG

273
Q

shine dalgarno function

A

allows independent translation of each ORF in polycistronic RNA

274
Q

shine-dalgarno function

A

allows independent translation of each ORF in polycistronic mRNA

275
Q

mutation in shine dalgarno

A

reduces specific ORF translation but not others

276
Q

difference between pro/eu translation

A

pro is coupled / trans affects txn
eu is uncoupled/ trans doesn’t affect txn

277
Q

haplotype

A

association of number of polymorphic markers

278
Q

variable number tandem repeats cause

A

unequal crossover/ replication errors

279
Q

microsatellites

A

GC-rich, variant repeats of ~5 nucleotides
e.g. SSR/ STR

280
Q

Paternity testing

A

PCR testing of minisatellites
DNA-17 profiling

281
Q

DNA-17 profiling

A

detects STR’S/ STR loci

282
Q

SNP/ single nucleotide polymorphism

A

single base differences
produce new sites for restriction endonucleases

283
Q

RFLP

A

Restriction fragment length polymorphism

284
Q

CpG islands

A

associated w promoters
enriched w CpG sites
identified when sequence unknown due to restriction enzyme clustering
associated with 5’

285
Q

SNP map functions

A

locating genes associated w phenotypes
diagnosis of problems/ phenotypes

286
Q

international HAPMAP project

A

SNP maps of human genome
haplotypes used as tool for genotyping and examination
analysed via bead/gene chips

287
Q

bead chips

A

PCR amplification of whole genome
fragments DNA into smaller pieces and hybridizes primers bound to beads on chip

288
Q

genome wide association study pros

A

informs patient care/screening/ human history
insurance
gene identification influencing phenotypes

288
Q

multigene family

A

group of genes descending from common ancestor and therefore having similar functions / genotypes

289
Q

how do multigene families arise

A

duplication events followed by mutation generating alterations in function/expression

290
Q

function of hox genes

A

encode transcription factors influencing expression patterns of genes during development

291
Q

homeobox

A

180 nucleotide segment wncoding DNA binding ‘homeodomain’

292
Q

primitive globin

A

monomeric
single O2 binding

293
Q

thalassemia

A

alpha/beta chain production in unequal amounts leading to abnormal Hb

294
Q

cause of thalassemia

A

mutation in a/b globin genes
severity depending on no. affected genes and mutation severity

295
Q

B thalassemia

A

2b genes
1 mutated=minor
2 mutated= major

296
Q

de novo generation

A

neutral/advantageous transcription of part of genome, evolving over time as new gene

297
Q

In which cell-type is Baculovirus used as a cloning and expression vector for recombinant genes?

A

insect

298
Q

Which enzyme is used to make a cDNA copy of mRNA?

A

reverse transcriptase

299
Q

multiple cloning site

A

polylinker

genetics semester 1 (6 decks)

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