Brainscape's Knowledge GenomeTM

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


See full index

Microbio > Microbial Genetics (8 and 9) > Flashcards

Microbial Genetics (8 and 9) Flashcards

1
Q

DNA as genetic material

A
  • Griffith discovers transformation in 1928
  • cells uptake free DNA from lysed cells
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

smooth vs. rough strains of strep.pneumonieae

A

smooth: have capsule, cause pneumonia
rough: don’t have capsule, do not cause pneumonia
transformation principle: rough could take up DNA that cause pneumonia

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

flow of genetic material

A

Central Dogma
DNA to RNA to protein

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

DNA structure

A
  • nucleotide polymers
  • ATGC (adenine, guanine, cytosine, thymine)
    • A and T: 2 hydrogen bonds
    • G and C: 3 hydrogen bonds
  • phosphodiester bonds: 3’ to 5’
  • deoxyribose
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

RNA structure

A
  • nitrogenous base differs from DNA
  • AUGC (adenine, guanine, cytosine, uracil)
  • ribose
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

semi-conservative synthesis

A

separate into templates for new strand

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

patterns of DNA synthesis

A
  • most bacterial DNA is circular
  • origin of replication
    • 2 forks
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

DNA replication machinery: DNA polymerase

A
  • I through V
  • adds bases to template
    • I and III: key role in synthesis
    • 5’ to 3’ direction
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

DNA replication machinery: DnaA

A
  • initiation factor
  • assembles at origin, slowly unravels small amount of DNA
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

DNA replication machinery: DnaB

A
  • helicase
  • “unzipping” DNA to break hydrogen bonds between bases
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

DNA replication machinery: Single-stranded DNA binding proteins (SSBs)

A
  • prevent premature reconnecting (keeps zipper open)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

DNA replication machinery: Topoisomerase IV

A

separates interlocked chromosomes

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

DNA replication machinery: gyrase

A

eases strain of DNA replication

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

DNA replication process

A
  1. DNA polymerase synthesis
  2. termination
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

DNA replication process: DNA polymerase synthesis

A

5’ to 3’ direction only
- leading strand: polymerase III
- lagging strand: okazaki fragments
- small amounts synthesized, move through SSBs

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

DNA replication process: termination

A
  • Tus @ termination site
  • topoisomerase IV separates catenones (joined chromosomes)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Gene structure: general info

A
  • basic unit of genetic information
  • sequence codes for a product
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

protein-coding genes: template strand

A

directs RNA synthesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

protein-coding genes: components

A
  • template strand
  • promot
  • pribnow box
  • shine-dalgarno sequence
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

protein-coding genes: promot

A
  • RNA polymerase recognition and binding
  • contains pribnow box
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

protein-coding genes: pribnow box

A
  • in promot
  • similar to TATA box
  • synthesizes leader, triggered to leave at terminator
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

protein-coding genes: shine-dalgarno sequence

A

on mRNA
- aligns ribosome with start codon

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

RNA synthesis: RNA polymerase

A
  • subunits: a, B, B’, W
  • sigma factor: doesn’t catalyze, helps polymerase recognize promoter
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

RNA synthesis: phases

A

initiation, elongation, termination

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

RNA synthesis: initiation

A
  • starts at promoter
  • sigma factor
  • bacterial promoters
    • TTGACA (-35)
    • Pribnow-TATAAT (-10)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

RNA synthesis: elongation

A
  • RNA polymerase: unwinds DNA, moves along template, synthesizes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

RNA synthesis: termination

A
  • RNA polymerase dissociation from template DNA
  • terminator (intrinsic, rho factor)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

intrinsic termination

A
  • pauses, stem loop forms stopping RNA polymerase
  • uracil-rich region
  • factor independent
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

rho factor termination

A
  • binds to rut site
  • splits DNA from RNA
  • breaks hydrogen bonds
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

genetic code: codon

A
  • 3 nucleotide set
  • specifies amino acid
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

start codon

A

AUG: codes methionine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

sense codon

A
  • 61 total
  • codes amino acid
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

nonsense codon

A
  • terminal
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

code degeneracy

A

mutations due to multiple options for 1 amino acid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

polypeptide synthesis directed by?

A

sequence of nucleotides in mRNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

ribosome during polypeptide synthesis

A

site of translation

37
Q

bacterial polypeptide synthesis

A
  • 900 AA/min
  • coupled transcription and translation on polyribosome complex
38
Q

tRNA during polypeptide synthesis

A
  • anticodon to ribosome
    • binds to mRNA
  • acceptor stem
    • holds amino acid
39
Q

polypeptide synthesis: initiation

A
  • initiation complex with met-tRNA, 30s subunit, mRNA
  • factors 1, 2, and 3: catalyze addition of 50s subunit
40
Q

polypeptide synthesis: elongation

A
  • P, A, and E sites
41
Q

polypeptide synthesis: termination

A
  • nonsense codon
    • UAA, UAG, UGA
  • release factors: aid in recognition of stop codon
42
Q

maturation and secretion: general rules

A
  • function depends on 3D shape
  • post-translational event
    • requires folding
    • association with other proteins
    • proper subcellular and extracellular sites
43
Q

translocation

A
  • movement from cytoplasm to periplasm or plasma membrane
    • past membrane
44
Q

translocation: sec

A
  • both eukarya and bacteria
  • transports unfolded proteins
45
Q

translocation: tat

A
  • unique to bacteria
  • transports folded proteins
46
Q

translocation: YidC

A
  • unique to bacteria
47
Q

sec proteins: 3 types

A
  1. secA: outside pump
  2. secYEG: transmembrane
  3. secDF: assists
48
Q

secretion

A
  • movement out of cell
  • cytoplasm to external environment
  • role in toxicity
49
Q

secretion type I

A

translocation through membrane, secrete out of cell

50
Q

secretion type II

A

anchor, no translocation

51
Q

secretion type III

A

acts like a syringe
- injectisome protrudes and contacts host cell

52
Q

secretion type IV

A
  • can make contact
  • usually for conjugation
53
Q

secretion type V

A

just secretion, no plasma membrane association

54
Q

secretion type VI

A
  • contracted and expanded versions
  • expanded contacts host
55
Q

mutations: definition

A

changes in genetic material

56
Q

point mutation

A

change in single base pair

57
Q

spontaneous mutation

A

arise naturally in absence of mutagen

58
Q

induced mutation

A

caused by a mutagen

59
Q

protein coding gene mutations: silent

A

different code, same amino acid

60
Q

protein coding gene mutations: missense

A

codes for different amino acid
- severity ranges

61
Q

protein coding gene mutations: nonsense

A

codes for stop
- most detrimental

62
Q

protein coding gene mutations: frameshift

A

insertion or deletion shifts entire sequence

63
Q

auxotrophic mutation

A

unable to make an essential macromolecule
ex) lysine auxotroph

64
Q

resistance mutation

A

resistant to certain substance

65
Q

DNA repair: proofreading

A

DNA polymerase
- during replication

66
Q

nucleotide excision repair

A
  • UVrABCD endonuclease removes damaged nucleotides
  • caused by thymine dimers
67
Q

nucleotide excision repair: UvrA

A

scans for damage and binds to damaged portion of DNA

68
Q

nucleotide excision repair: UVrB

A
  • recruited to site by UVrA
  • directs UVrC to cut both sides of damage
69
Q

nucleotide excision repair: UVrC

A

cuts both sides of damage

70
Q

nucleotide excision repair: UVrD

A

removes damaged region

71
Q

nucleotide excision repair: DNA polymerase I and DNA ligase

A

fill and seal gap

72
Q

base excision repair: DNA glycosylase

A
  • recognizes abnormal base
  • cleaves bond between base and sugar
73
Q

base excision repair: AP endonuclease

A
  • recognizes missing base
  • cleaves backbone on 5’ side
74
Q

base excision repair: DNA polymerase

A
  • uses 5’-3’ exonuclease activity to remove damaged region
  • fills it in with normal DNA
  • ligase seals region
75
Q

recombination repair

A
  • initiates repair of DNA damage on both strands
  • RecA corrects damage
76
Q

genetic recombination

A

new nucleotide sequence formed via rearrangement

77
Q

horizontal gene transfer: general info

A
  • differs from vertical gene transfer
  • gene transfer from one independent mature organism to another
  • important in evolution
    • antibiotic resistance
    • virulence
78
Q

horizontal gene transfer: conjugation

A
  • unidirectional
  • F factor (F+ and F- mating)
  • copy of F factor transferred to recipient
79
Q

rolling circle mechanism: steps

A
  1. sex pili contracts, bringing donor and recipient closer together
  2. T4SS constructed and cells join
  3. relaxosome cuts at oriT and begins to separate one strand
  4. relaxosome accessory proteins released, coupling factor recognizes DNA/relaxase, transfers it to T4SS
  5. T4SS pushes DNA/relaxase into recipient
    Product: 2 F+ cells
80
Q

rolling circle mechanism: donor and acceptor

A

F+: donor
F-: acceptor

81
Q

transformation

A

uptake and incorporation of DNA by competent cells

82
Q

s. pneumoniae transformation steps

A
  1. fragment binds
  2. nuclease activity
  3. DNA enters cell
  4. integrates into host chromosome
83
Q

DNA uptake: uptake pilus

A

pulls DNA past peptidoglycan layer

84
Q

DNA uptake: ComEA

A

directs to ComEC

85
Q

DNA uptake: ComEC

A

stripped into single strand by nuclease

86
Q

transduction

A

transfer of bacterial genes by viruses

87
Q

transduction: lysogenic

A
  1. phage integrates into chromosome
  2. prophage copied during cell division
  3. excision
88
Q

transduction: lytic

A
  1. phage injects DNA
  2. phage DNA directs synthesis of new phages that can bind to cell after lysis
  3. lysis

Microbio (11 decks)

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