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Reproduction in Microbiology Flashcards

1
Q

Binary fission

A
  1. Cells first did quarum sensing to sense increase in size and number
  2. Replicate
  3. elongate
  4. Form a septum to degrade peptidoglycans in order to split cells apart. (Most susceptible to antibiotics at this point)
  5. Completion of individual distinct walls and separation
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2
Q

FTS proteins

A

regulate cell division and chromosome replication and interact to form a divisome at midpoint

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3
Q

FTSZ

A

completely surround the cell and forms a plane in prokaryotes and Mre proteins that define shape at divisiome

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4
Q

autolysins

A

degrade existing peptidoglycan

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5
Q

MIC

A
  1. Minimum inhibitory concentration that would stop the formation of the FtZ ring
  2. When an antibiotic is made for this bacteria the divisiome is scattered and elongated throughout cell.
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6
Q

bactoprenol

A

is a hydrophobic alcohol that faciliates the transfer of new glycan units across cytoplasmic membrane for formation of peptidoglycan

Can be inhibited by vancomycin

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7
Q

Transpeptidation

A

Tetrapeptide and a pentapeptide connect via a transpeptidase to create a peptide bond leading to 2 tetrapeptides

Inhibited by penicillin

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8
Q

Vancomycin

A

treats multi-resistant gram negative infections by binding (D-ala-D-ala) part of pentapeptide that is used for inter bridge

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9
Q

Plectasin

A

binds to different sites of pentapeptide to inhibit it

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10
Q

Beta-lactamase

A
  1. Capable of destroying penicillin
  2. Antibiotics that are resistant are : cephlosporins, carbapemens
  3. Beta lactamases have evolved to resist second generation antibiotics
  4. 890 species discovered
  5. NDM-1 has 180 kb and multiple resistance genes which hydrolyze penicillin and cephlasporins
  6. Another beta lactamases inactivate: erythromycin, cipro, chloramphenicol.
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11
Q

Exponential Growth

A
  1. Growth pattern of microbial populations
  2. Generation time: 1/2 hour of less
  3. 1 bacteria becomes 1 million in 10 hours or less
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12
Q

Lag Phase

A

Preparing for binary fission (grow in mass not #)

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13
Q

Log phase

A

Increase in mass and # due to growth rate and generation time (susceptible to antibiotics)

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14
Q

Stationary Phase

A

of viable bacteria does not increase but still have cell division

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15
Q

Death

A

of viable bacteria is decreasing

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16
Q

Methods for determining bacterial concentrations

A
  1. Direct microscopic count
  2. Plate count of colonies
  3. Optical density
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17
Q

Direct microscopic count

A

Petroff Hauser counter-counting chamber of defined volume
Total Squares: 25
Total volume: .02mm3
Advantage: quick
Disadvantage: Doesn’t distinct between live and dead and hard to count if bacteria are mobile

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18
Q

Plate count of colonies

A
  1. Sample of bacteria is placed on agar and spread out
  2. Incubated for 48 to 72 hours
  3. Count surface colonies=viable bacteria
    Subsurface colonies are those that live in the gingiva and have strict oxygen restrictions

Advantage: Most accurate
Disadvantage: Long wait (48-72hours)

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19
Q

Serial Dilution in plate count

A

Number of colonies on agar are directly proportional to number of viable bacteria in liquid culture

  1. Take plate count and multiple by dilution factor
  2. Less dilution =more colonies
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20
Q

Optical Density

A

Spectrophotometric method: bacteria can scatter light and and the unscattered light (absorbed) is measure in klett units. Klett units represent density of the culture

Advantage: quick
Disadvantage: higher concentration of cells causes the relationship between optical density and cell # to break down

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21
Q

obligate aerobe

A
  1. require oxygen

2. aerobic respiration

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22
Q

facilitative aerobe

A
  1. oxygen is not require but grow better with it

2. aerobic respiration, anaerobic respiration and fermentation

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23
Q

microaerophilic aerobe

A
  1. require oxygen but grow better at a low atmospheric pressure
  2. aerobic respiration
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24
Q

aerotolerant anaerobe

A
  1. do not require oxygen

2. anaerobic respiration

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25
obligate anaerobe
1. oxygen is harmful and lethal | 2. fermentation and anaerobic respiration
26
thioglycollagate
added to a medium to test oxygen requirement
27
superoxide
toxic oxygen species
28
reactive oxygen molecules:
1. superoxides (O2) 2. hydrogen peroxide 3. hydroxyl radicals (OH)
29
Enzymes that neutralize oxygen
1. superoxide dimutase: converts superoxides into hydrogen peroxide 2. catalase: converts hydrogen peroxide into water and oxygen 3. perioxidase: converts hydrogen peroxide into water
30
catalase test
1. drop of hydrogen peroxide is added to bacteria to test if it is able to convert it into water and oxygen
31
Cardinal temperatures
1. Minimum 2. Optimum 3. Maximum
32
Psychrophiles
Can grow between 0-12 degrees celcius | Example: Palaromonas Vacuolate
33
Mesophiles
Can grow between 10-50 degrees celcius | Example: E Coli
34
Thermophiles
Can grow between 40-70 degrees celcius | Example: Bacillus stearothermophilias
35
Hyperthermophiles
Can grow between 65-100 degrees celcius | Example: Thermococcus Celer
36
Extreme hyperthermophiles
Can grow between 90-110 degrees celcius | Example: pyrolobus fumarii
37
Taq polymerase
automate the repetitive steps in the PCR (polymerase chain reaction) -polymerization of DNA
38
pH
absolute value of the exponent molar concentration of hydrogen ions in a solution
39
pH ranges bacteria will tolerate
Human Microbes: 5-8 Human blood: 7.35 Acidophiles: (Lactobacilli) 5.5
40
Stephans Curve
Ability of oral bacteria to produce acid in the presence of glucose (sugar) 1. The quicker the recovery period the less caries 2. With slower recovery lactic acid is present longer and the incident of caries increases
41
What would change stephens curve
1. Adherence factors of bacteria 2. Present of antibodies (high-low concentration) 3. Buffer (saliva)
42
pH changes in the mouth
Plaque in the mouth can cause localized changes in pH
43
Salt/Water control
Bacteria like high water and low salt concentrations
44
Xerophiles
1. Microbes grow in very dry enviroments 2. Water is limiting to organism when solute concentration is increasing 3. To keep positive water balance it uses compatible solutes
45
Halophiles
1. Like High salt and low water | 2. Halotolerant-can tolerate a reduction in water but grow best in an absence of solutes
46
Nonhalophile example
E Coli
47
Halotolerant example
Staph Aureus
48
Halophile Example
Vibrio Fischeri
49
Extreme Halophile
Halobacterium Salinarum
50
Reverse Transcription
converting RNA into a DNA format
51
Flow of genetic information from DNA to RNA requires
Promotor
52
Polycistronic Message
Produced from the flow of genetic information from DNA to RNA (Transcription)=RNA message with many coding regions
53
Prokaryote genes:
1. Contain a contiguous coding region | 2. Upstream regulatory proteins
54
Eukaryotic genes
1. Several exons with introns falling in between. | 2. Regulatory regions that do not code for protein but regulate transcription
55
prokaryotic DNA
1. Circular double standed DNA | 2. Supercoiled
56
Simplest form of DNA strand
Alpha helix with a major and minor groove that has a net negative charge
57
DNA Characteristics
1. DNA is bendable 2. ds-alpha helix is formed due to stretchiness within the complementary strands (Stem loop) 3. DNA absorbs light at 260 nm 4. Single stranded DNA absorbs more light than double stranded DNA 5. When DNA is melted absorbance increases 6. Average melting temperature is 85 degrees celcius 7. DNA in E Coli has 4.7 Million bases
58
Prokaryotic Chromosomes/plasmids
Chromosomes: long, double stranded, circular DNA Plasmid: short, circular , double stranded DNA
59
Eukaryotic Chromosomes/Plasmids
Chromosomes: usually long, double stranded, linear DNA Plasmid: short, double stranded circular or linear DNA
60
Transposable elements
Double stranded DNA found within another DNA molecule (in all organisms)
61
Mitochondria Chromosomes
Circular DNA
62
Virus Genome
RNA or DNA and Double strand or Single strand
63
Class I Topoisomerase
Introduces single strand breaks to supercoiled DNA that is needed for replication of DNA and cell division -This will relax the supercoil for replication and transcription
64
Class II Topoisomerase
Introduces double strand breaks into supercoiled DNA
65
DNA gyrase
This is how DNA is supercoiled along with Class II topoisomerase
66
Inhibitors of gyrase
1. Nalidixic acid 2. Cipro 3. Nobobiocin
67
Supercoiling Domains
1. Domains held together by proteins | 2. Prevents DNA from uncoiling when nicked
68
Eukaryotic supercoiling
DNA is wrapped around histones and form nucleosomes
69
restriction enzymes
cut foreign DNA to analyze and is a defense mechanism 1. From bacteria 2. Cut specific sequences 3. Palindromic sequence 4. DNA can then be cut into shorter fragments 5. Unmethylated sequences will be cut
70
Cutting DNA
restriction enzymes cut and leave sticky ends that are complementary but unbound so you add DNA and reanneal below melting temperature
71
Requirement for DNA replication
1. DNA Polymerase-attaches nucleotides 2. Helicase-unwinds DNA and binds near replication fork 3. Primase-short starter chains of RNA 4. Ligase-seals it into a single structure 5. Gyrase-supercoiling 6. Topoisomerase-relax supercoiling
72
Characteristics of DNA Replication
1. Origin of replication that allows for it to occur in both directions simultaneously 2. DNA polymerase III is used for proofreading 3. DNA polymerase I is used for removing primer and filling if gaps (can also do DNA repair)

Microbiology (4 decks)

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