Chapter 7 Microbial Genetics Flashcards

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1
Q

DNA

A

deoxyribonucleic acid

-encodes the genetic instructions used in the dvlpt and functioning of all known living organisms and many viruses

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2
Q

Genetics

A

the study of inheritance and inheritable traits as expressed in an organisms genetic material

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3
Q

Genome

A
  • entire genetic complement of an organism

- includes its genes and nucleotide sequence

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4
Q

Phosphodiester bonds

A

covalently bonded pentose molecules that connects the sides of the DNA ladder
-strong

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5
Q

Nitrogenous bases

A

Adenine
Thymine
Guanine
Cytosine

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6
Q

Complementary Bases

A

Adenine-Thymine/Uracil

Guanine-Cytosine

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7
Q

Prokaryotic Genome

A
  • Nucleoid: circular DNA
  • plasmids
  • RNA + ribosomes
  • haploid
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8
Q

Haploid

A

single chromosome copy

-one copy of each genes

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9
Q

Plasmids

A
  • small circular pieces of DNA that replicate independently
  • separate from nucleoid
  • not essential for normal metab, growth, + reproductions
  • survival advantage
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10
Q

types of Plasmids

A

1 fertility factors
2 resistance factors
3 bacteriocin factors
4 virulence plasmids

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11
Q

Fertility Factors Plasmids

A

ability to produce sex pilus

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12
Q

Resistance Factors Plasmids

A

R factors,

antibiotic resistance

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13
Q

Bacteriocin Factors Plasmids

A

toxins produced by bacteria to inhibit growth of other closely related bacteria

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14
Q

Virulence Plasmids

A

code of virulence factors

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15
Q

DNA replication

A
  • generates a complementary structure of the 2 strands of DNA
  • semiconservative
  • anabolic polymerization process
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16
Q

Process of Bacterial DNA replication

A
  • begins at origins site
  • DNA polymerase replicates DNA from 5’ to 3’
  • Strands are antiparallel new strands are synthesized differently
  • -leading strand is synth continuously
  • -lagging strand is synth discontinuously
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17
Q

Genotype

A

set of genes in the genome

-genotype determines phenotype

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18
Q

Phenotype

A

physical features and functional traits of the organism

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19
Q

Gene Function

A
  • TRANSCRIPTOIN
  • TRANSLATION
  • CENTRAL DOGMA OF GENETICS
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20
Q

TRANSCRIPTION

A

information in DNA is copied as RNA

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21
Q

TRANSLATION

A

polypeptides are synthesized from RNA

-participants: mRNA, tRNA, ribosomes+ rRNA

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22
Q

Central Dogma of Genetics

A
  • DNA is transcribed to RNA

- RNA is translated to form polypeptide

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23
Q

transcription + translation in bacteria

A

cytoplasm

-coupled: transcrip+translat happen at the same time

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24
Q

3 steps of Transcription

A

1 initiation
2 elongation
3 termination

  • all stages require additional protein factors
  • initiation + elongation require energy (GTP)
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25
Q

transcription + translation in bacteria

A
  • occurs in cytoplasm

- coupled: transcrip+translat happen at the same time

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26
Q

Nucleoid

A
  • prokaryotic version of nucleus

- circular DNA

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27
Q

transcription in eukaryotes

A
  • RNA transcription occurs in nucleus
  • -3 types of RNA polymerase, numerous transcription factors
  • mRNA is processed before translation
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28
Q

where is the location of DNA in prokaryotes

A

in nucleoid of cytoplasm and in plasmids

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29
Q

histones are found in_____

bacteria, archaea, or eukarya

A

histones are found in archaea and eukarya

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30
Q

type of nucleic acid in bacteria

A

circular or linear dsDNA

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31
Q

semiconservative

A

-new DNA is composed of 1 original + 1 daughter

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32
Q

anabolic polymerization process

A
  • requires monomers + energy (ATP)

- deoxyribonucleotides (dGTP) serve both functions

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33
Q

Leading Strand

A
  • continuous synthesis

- creating 5’ to 3’ starting on 5’

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34
Q

Lagging strand

A
  • discontinuous synthesis

- creating 5’ to 3’ starting on 3’

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35
Q

Key differences w eukaryotic DNA replication

A
  • uses 4 DNA polymerase
  • thousands of replication origins
  • shorter Okazaki Fragments
36
Q

Codon

A

3 base pairs that translates into a peptide

37
Q

mRNA

A

-copy of recipe/original DNA

38
Q

rRNA

A

-codes for ribosomes

39
Q

tRNA

A

-chef helpers

40
Q

RNA polymerase

A

makes RNA, uses Uracil instead of thymine

41
Q

eukaryote vs prokaryote ribosomes

A
prokaryote = 70s ribosome (50s+30s subunits)
eukaryote = 80s ribosome (60s+40s subunit)

pro is smaller than eu ribosomes

42
Q

single prokaryotic mRNA can code for ______

A

-several polypeptides.

43
Q

Regulation of Genetic Expression

A
  • bacteria adapt to changes in their surroundings and regulate which genes they need to turn on/off
  • genes are transcribed and translated when cells need them
  • bacteria regulate expression of many genes based on food sources
44
Q

Quorum sensing

A
  • regulates production of some proteins based on food sources available
  • allows cells to conserve energy
45
Q

Prokaryotic Operons

A

-regulates genetic expression

46
Q

2 types of prokaryotic operons

A

1 Inducible Operons

2 Repressible Operons

47
Q

Inducible Operons

A

-must be activated by inducers

ex) lactose operon-
presence of lactose turns the genes for lactose digestive enzymes on

48
Q

Repressible Operons

A

-are transcribed continuously until deactivated by repressors

ex) tryptophan operon
presence of tryptophan turns the tryptophan synthesis enzyme off

49
Q

Genetic Mutation

A
  • change in nucleotide base sequence of a genome
  • rare
  • almost always deleterious
  • rarely leads to a protein that improves ability of organism to survive
50
Q

types of Mutation

A

1 Point Mutation

2 Frameshift Mutations

51
Q

Point Mutations

A
  • one base pair is affected

- substitutions

52
Q

Frameshift Mutations

A

-nucleotide triplets after the mutation are displaced
-creates a new sequence of codons
ex)
OG: AATTCC
Frameshift: AA[G]TTC

53
Q

Mutagens

A
  • things that generate mutations in genes

ex) radiation, chem mutagens, nucleotide-altering chems, and frameshift mutagens

54
Q

Radiation

A
  • ionizing and non ionizing radiation
  • type of mutagen

ex) UV light -wavelengths of UV disrupts the DNA

55
Q

chemical mutagens

A
  • nucleotide analogs: disrupts DNA and RNA replication

- carcinogen

56
Q

nucleotide-altering chemicals

A
  • type of mutagen
  • alter structure of nucleotides
  • result in base-pair substitutions and missence mutations
  • disrupts in DNA or RNA
  • carcinogen
57
Q

frameshift mutagen

A

-result in nonsense mutation

58
Q

4 examples of mutagens

A

1 radiation
2 chem mutagen
3 nucleotide-altering chemicals
4 frameshift mutagen

59
Q

frequency of mutations

A

1 in every 10million genes contains an error

  • mutagens increase the rate by a factor of 1,000x
  • many of mutations stop transcription or code for nonfunctional proteins
60
Q

DNA repair mechanisms

A
  • repair pathways exist so that we can correct the damage and repair the DNA
  • in humans, environmental factors and UV result in nearly 1million individual molecular lesions per day
61
Q

2 DNA repair pathways

A

1 LIGHT repair pathway

2 DARK repair pathway

62
Q

Mutants

A

descendants of a cell that does not repair a mutation

63
Q

Wild Type

A

cells normally found in nature

64
Q

Methods to recognize mutants

A

1 Positive Selection
2 Negative (Indirect Selection)
3 AMES test

65
Q

Genetic Recombinant

A

-exchange of nucleotide sequence occurs often bw homologous sequence

66
Q

Recombinants

A

cells with DNA molecules that contain new nucleotide sequences

67
Q

Vertical Gene Transfer

A

passing of genes to the next generation

68
Q

Horizontal Gene Transfer

A

-donor cell contributes part of genome to recipient cell

69
Q

4 types of Horizontal Gene Transfer

A

1 Transformation
2 Transduction
3 Conjugation
4 Transposon

70
Q

Transformation Horizontal Gene Transfer

A
  • recipient takes up the DNA from the environment
  • cells that take up DNA are competent
  • – results fr alterations in cell wall and cytoplasmic membrane that also DNA to enter cell
71
Q

Transduction Horizontal Gene Transfer

A
  • transfer of DNA from 1 cell to another via REPLICATING VIRUS
  • virus must be able to infect both donor and recipient cells
  • BACTERIOPHAGE
72
Q

Bacteriophage

A

virus that infects bacteria,

replicates using bacterial organelles, and then lyses

73
Q

Conjugation Horizontal Gene Transfer

A
  • genetic transfer requires physical contact bw donor and recipient cell
  • donor cell remains alive
  • mediated by CONJUGATION (SEX) PILI
74
Q

5 types of RNA

A
RNA primers
mRNA
tRNA
rRNA
regulatory RNA
75
Q

Transposon

A

segments of DNA that moves from one location to another in the same/different molecule
-results from a type of frameshift insertion (transposition)

76
Q

2 types of Transposons

A

1 simple transposon

2 complex transposon

77
Q

AMES test

A
  • used to determine mutants or the mutagenic potential of chemicals/microbes
  • cells are mixed w suspected mutagenic chemical; then check to see if mutations have occured
78
Q

AMES test

A
  • used to determine the mutagenic potential of chemicals/microbes
  • also determines mutants
79
Q

Frederick Griffith Test

A
  • demonstrated exchange of DNA via transformation

- proved heredity of DNA

80
Q

Promoter

A

part of the genes where transcription is initiated

81
Q

3 processes that need to occur before eukaryotic mRNA can be translated

A

-capping, polyadenylation, + splicing

82
Q

Methylation

A

adding a methyl group to dna from restricting enzymes

83
Q

Light Repair

A

-DNA repair for pyrimidine dimer with visible light

84
Q

Dark Repair

A

-DNA repair for pyrimidine dimer by removal of section w dimer. then DNA polymerase

85
Q

Pirimidine

A

thymine or cytosine dimers.

forms covalent bond and prevents hydrogen bonding

86
Q

AUG

A

start codon and methionine