Exam 1 9/14 Nguyen Micro Flashcards

1
Q

Central dogma

A

Dna to rna to protein

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2
Q

Purines

A

A and G

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3
Q

Pyrimidines

A

C, U, T

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4
Q

A-T has ___ H bonds

A

2

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5
Q

C-G has ___ H bonds

A

3

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6
Q

Direction of transcription

A

5 to 3 prime

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7
Q

Codons

A

each amino acid is defined by triplet code

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8
Q

Start codon on DNA

A

ATG

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9
Q

Start codon on RNA

A

AUG

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10
Q

Stop codon DNA

A

TAA, TAG, TGA

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11
Q

Stop codon RNA

A

UAA, UAG, UGA

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12
Q

True or false: bacteria do not contain histones

A

True

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13
Q

Merodiploid

A

Partial duplication of chromosome in cell; contains 2 copies of genes

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14
Q

Virulent strains of Vibrio cholerae may contain:

A

2 chromosomes
1st = essential cellular functions, PAIs
2nd = some essential cell functions, plasmid genes

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15
Q

DNA methylation in humans promotes formation of:

A

heterochromatin

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16
Q

Histone acetylation promotes the formation of:

A

euchromatin

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17
Q

Human genes may include what features?

A
  1. upstream repressor/enhancer sites
  2. promoter
  3. introns and exons
  4. distant enhancer
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18
Q

True or false: bacteria does not contain mitochondrial DNA or introns

A

True

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19
Q

Operon

A

composed of many genes controlled by a common promoter

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20
Q

Cistron

A

coding gene within an operon

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21
Q

Operons are generally _____

A

polycistronic

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22
Q

Operons have a common _____ for transcription

A

terminator

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23
Q

Operon promoter is recognized by:

A

RNA polymerase (initiates gene or cistronic transcription)

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24
Q

Operator another name

A

Regulator

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25
Q

Positive control

A

Inducible

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26
Q

Negative control

A

Repressible

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27
Q

What is a benefit for bacteria to have operons?

A

Synthesize all related enzymes “together”; fast and efficient environmental adaptation

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28
Q

Constitutive expression examples in bacteria

A

Transpeptidase, NAG, NAM

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29
Q

Negative control operon example

A

Trp operon

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30
Q

Positive control operon example

A

Lac operon

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31
Q

Which operons are examples of regulated expression?

A

Trp and Lac operon

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32
Q

Trp operon is expressed by ____, because:

A

default; trp is often missing

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33
Q

Describe what happens when trp operon is on

A
  1. repressor protein unable to bind DNA
  2. polycistronic mRNA transcribed
  3. trp A-E make tryptophan synthetase
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34
Q

Function of trp operon

A

Makes more tryptophan when concentration of tryptophan is low in the cell

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35
Q

If tryptophan is present in the environment, then:

A

tryptophan triggers repression
- tryptophan binds repressor protein
- tryptophan + repressor bind DNA
- blocks RNA polymerase so it cannot make mRNA

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36
Q

In lac operon, if glucose is low and lactose is available, then:

A

lac operon is expressed to make lactase

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37
Q

Transcriptional regulation of lac operon

A

not expressed by default, is inducible; repressor binds to operator so RNA Pol can’t bind to promoter

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38
Q

In lac operon, when lactose is present:

A
  1. allolactose protein binds to repressor, released from operator site on DNA
  2. RNA Pol binds to promoter to allow transcription
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39
Q

Catabolite activator protein (CAP)

A

Glucose sensor

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40
Q

Hunger molecule

A

cAMP

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41
Q

E. coli makes ___ when low in glucose

A

cAMP

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42
Q

Alternative regulator of lac operon

A

CAP-cAMP

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43
Q

When CAP-cAMP binds to DNA:

A

increases transcription of lac operon

44
Q

CAP acts as a:

A

lac operon repressor

45
Q

When glucose is present, ____ cAMP

A

low

46
Q

When glucose is low, ____ cAMP

A

high

47
Q

Pathogenicity islands (PAIs)

A

selective advantage to virulent or pathogenic strains, can regulate many operons at one time

48
Q

Binary fission

A

Splits into 2 cells

49
Q

OriC

A

replication initiation site

50
Q

Replication fork

A

Where dna is splitting

51
Q

Topoisomerase

A

unwinds DNA

52
Q

helicase

A

separates dna strands

53
Q

RNA primase

A

makes rna primers

54
Q

DNA polymerase

A

adds nucleotides

55
Q

gyrase

A

supports elongation

56
Q

Leading strand

A

adds nucleotides to 3’ end

57
Q

Lagging strand

A

cannot add nucleotides to 5’ end, okazaki fragments have to be made

58
Q

DNA ligase

A

replaces rna primer with dna, joins okazaki fragments

59
Q

Genetic variation can be caused by:

A

mutation, gene transfer

60
Q

Transition replacement

A

purine replaced with purine; pyrimidine switched with another pyrimidine

61
Q

Transversion replacement

A

purine switched for pyrimidine
pyrimidine switched for purine

62
Q

Types of mutations

A

deletion, insertion, inversion, translocation, replication slippage

63
Q

replication slippage mutation

A

Slipped-strand mispairing

64
Q

Tandem repeats

A

large number of repeats, forma a loop

65
Q

Silent mutation

A

results in same amino acid

66
Q

Nonsense

A

insertion of stop codon - may have partial protein function

67
Q

Missense

A

results in different amino acid

68
Q

Proofreading repair

A

done by DNA Polymerase - detects and replaces incorrect nucleotide in just made dna

69
Q

Restriction endonucleases

A

excision repair/damage repair; defensive mechanism, creates palindromes, uses in genetic engineering

70
Q

CRISPR

A

clustered regularly interspaced short palindromic repeats

71
Q

Very precise gene editing tool

A

CRISPR

72
Q

Cas

A

CRISPR associated protein

73
Q

Cas function

A

guide recognizes and cuts specific dna strands

74
Q

Prokaryotes SOS dna repair is used for:

A

extensive dna damage – error prone

75
Q

Mutation rate ____ during SOS repair

A

Increases; increases drug resistance

76
Q

Gene transfer methods

A

conjugation, transduction, transformation, transposition

77
Q

Conjugation

A

bacterial sex

78
Q

Transduction

A

Viral infection

79
Q

Transformation

A

taking foreign dna

80
Q

Transposition

A

jumping genes

81
Q

Plasmids r factor

A

Resistance

82
Q

Plasmids f factor

A

Fertility

83
Q

True or false: plasmids can be found in both gram + and - bacteria

A

true

84
Q

Plasmid is located:

A

not on chromosome

85
Q

Plasmids can be transferred between bacteria via

A

sex pilus

86
Q

Plasmids multiply ___ of chromosome

A

Independently

87
Q

Can plasmids be inherited by daughter cells?

A

Yes

88
Q

Plasmids help bacteria confer

A

antibiotic resistance

89
Q

F+

A

plasmid containing; donor; forms sex pilus

90
Q

Donor and recipient of plasmid

A

Both F+

91
Q

Plasmid F-factor transfer

A
  1. double strand dna separate at OriT
  2. rolling replication - both strands make complementary strands
92
Q

Hfr

A

High frequency recombination cells - derivative of F+ cells
- when F plasmid becomes incorporated into the chromosome

93
Q

R plasmid confers resistance to protect cells from:

A

heavy metals, enzyme attacks, antibiotics (confers antibiotic resistance)

94
Q

Beta lactamase

A

Cleaves beta lactam ring, inactivates penicillin

95
Q

Plasmids can have ___ gene to sequester iron

A

siderophore

96
Q

Bacteriocin

A

inhibits growth of closely related species

97
Q

Lytic pathway

A

virulent phages

98
Q

Lysogenic pathway

A

Temperate phages, forms prophage where phage dna remains dormant; certain triggers can cause to go back to lytic phase

99
Q

Phage encoded exotoxin genes

A

Host produces exotoxins that are controlled by phage genes, toxins released when cell lyses

100
Q

Transformation summary

A
  1. transfer of exogenous bacterial dna
  2. taken up by competent cells
  3. recombined with the recipient cell dna or as plasmid
101
Q

Homologous recombination

A

break and recombine, can alter coding sequences and genes, usually within genera or genus

102
Q

Transposable elements contain:

A
  1. insertion sequences
  2. transposon dna’s
  3. transposase enzymes
103
Q

Transposase enzymes

A

endonucleases to cut and ligases to paste dna

104
Q

Transposition causes genes to move from:

A

one dna location to another. requires little/no homology, can alter genes and coding sequences

105
Q

Pathogenicity islands are different from operons in that:

A

biochemically unrelated but function synergistically

106
Q

Other isolated genetic islands are separated by:

A

GC-rich regions

107
Q

Fitness or persistence islands may code for:

A

survival traits - not strictly virulence factors (e.g. biofilm formation)