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Microbiology > Exam #2 > Flashcards

Exam #2 Flashcards

1
Q

What are bacteria made of ?

A

Water: 80-90%

Dry weight:

  • protein 50%
  • lipids 8-10%
  • RNA 10-20%
  • DNA 1-3%
  • peptidoglycan 2.5-10%
  • intracellular polymers: varies
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2
Q

What are the 3 nutritional types of bacteria and other microorganisms?

A

1) carbon source
2) electron source
3) energy source

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3
Q

What is the carbon source in the nutritional types of bacteria

A

1) Autotrophs: self feeders, CO2 is primary carbon source

2) heterotrophs: reduced organic molecules from other organisms

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4
Q

What is the electron source in the nutritional types of bacteria

A

1) Lithotrophs: reduces inorganic compounds(Fe, hydrogen gas, H2S)
2) Organotrophs: organic molecules

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5
Q

What is the energy source in the nutritional types of bacteria

A

1) phototrophs: light

2) Chemotrophs: oxidation of organic or inorganic compounds

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6
Q

What are we and most pathogens in the nutritional types

A

Chemo-organo-Heteroph

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7
Q

How do nutrients enter the cell?

A

1) diffusion
2) facilitated diffusion
3) active transport

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8
Q

What is diffusion

A

Passive flow of dilution down its concentration gradient

High to low concentration

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9
Q

What is facilitated diffusion

A

Passive flow of solute down its concentration gradient through a transporter

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10
Q

What is active transport

A

Movement of solute across membrane (often against a concentration gradient) through the use of ATP

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11
Q

Active transport is often carried out by what

A 
By the ABC superfamily of transporters 
   - well conserved 
   - membrane proteins 
   - in bacteria pump in and out 
        Influx requires the use of periplasmic binding proteins
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12
Q

What is another way to concentrate nutrients inside a cell (group transfer) ?

A
  • Nutrients are trapped in the cell after they are chemically modified (tag is added)
    Tagged nutrient inside the bacterial cell is removed from the concentration gradient of the original nutrient, so diffusion continues
  • phosphotransferase
    Carb out + PEP(in) —-> carb(in) with P attached + pyruvate (in)
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13
Q

What is binary fission?

A

One other cell splitting into 2 equal daughter cells

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14
Q

Binary fission can be ?

A

Symmetrical* or asymmetrical

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15
Q

Caulobacte, hyphomicrobium reproduce by budding

A

Know this

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16
Q

Eukaryotic microbes divide via mitosis

A

Know this

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17
Q

Growth curve has 4 stages , what are they

A

Lag phase
Log phase
Stationary phase
Death phase

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18
Q

What is lag phase

A

Bacteria are preparing their cell machinery for growth

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19
Q

What is log phase

A

Growth approximates an exponential curve (straight like in a logarithmic scale)

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20
Q

What is stationary phase

A

Cells stop growing and shut down their growth machinery while turning on stress responses to help retain viability

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21
Q

What is death phase

A

Cells begin to die at an exponential rage

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22
Q

At threshold, all bacteria realize

A

Virulence factors (toxins)

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23
Q

What is the equation for the viable count (cfo/ml)?

A

colonies/volume plated X reverse dilution factor

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24
Q

CFU means what

A

1 bacteria or clump of attached bacteria

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25
Q

How turbid is an sample? More bacteria means

A

More turbid

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26
Q

What is optimum temperature

A

Every organism has an optimum temp. At which it grows most quickly. Minimum and maximum temps define the limits of growth.

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27
Q

When does growth stop?

A

Rising temperatures cause critical enzymes or cell structures to fail

At cold temps, enzymatic processes become too sluggish and the cell membrane is less fluid

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28
Q

At what temps can psychrophiles grow at?

A

They can for at temperatures as low as 0C But their optimum growth temperature is around 14C

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29
Q

At what temps can Mesophiles grow at?

A

Have optimal growth between 20-40C, with a minimum of 15C and a maximum of 45C

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30
Q

At what temps can Thermophiles grow at?

A

Have adapted to growth at high temperatures, typically at 55C and higher

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31
Q

At what temps can Hyperthermophiles grow at?

A

Can grow at temperatures as high as 121C

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32
Q

Aerobe VS Anaerobe

A

Aerobe use oxygen as a terminal electron acceptor in the electron transport chain to extract energy trapped in the nutrients and convert it to a biologically useful form

^ need to know?

The use of O2 as the terminal electron acceptor is called aerobic respiration

Anaerobs , oxygen is toxic to them!!

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33
Q

What are strict aerobes

A

Organisms that not only exists in oxygen but also use oxygen as a terminal electron acceptor. They grow only when oxygen is present and consume oxygen during metabolism

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34
Q

What are strict anaerobes

A

They die in the least bit of oxygen. They do not use oxygen as an electron acceptor and die bc they are vulnerable to the highly toxic, chemically reactive oxygen species produced by their own metabolism when exposed to oxygen.

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35
Q

Reactive oxygen species (ROS) are what

A

Oxygen molecules or ions with one too few or too many electrons

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36
Q

Aerobes, but not anaerobes, destroy ROS with the aid of enzymes such as ? (3)

A

1) superoxide dismutase (to remove superoxide)
2) peroxidase (to remove hydrogen peroxide)
3) catalase (to remove hydrogen peroxide)

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37
Q

Aerobes also contain resoureful enzymes systems that detect and repair macromolecules damaged by oxidation

A

Know this

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38
Q

Most microbes in the world are

A

Anaerobic

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39
Q

What must organisms rely on when you don’t have electron transport chain?

A

They must rely on carbohydrate fermentation for energy

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40
Q

What are facultative anaerobes

A

That possess that enzymes to detoxify oxygen radicals and also the machinery for both fermentation and aerobic respiration

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41
Q

What are aerotoletant anerobes

A

Use only fermentation to provide energy but contain superoxide dismutase and catalase or peroxidase to protect from ROS

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42
Q

What are microaerophiles

A

Will grow only at low oxygen concentrations. They possess a decreased level of superoxide dismutase and/or catalase

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43
Q

What is evolution

A

1) change upon lines of descent
2) results from cumulative changes in the genetics of a population from generation to generation
3) can also result from “horizontal gene flow” movement of DNA between species

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44
Q

What is the endosymbiotic hypothesis

A

Mitochondrial are remnants of a bacterium that was eaten by an early eukaryote and allowed to persist

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45
Q

What are some of the evidence of the endosymbiotic hypothesis

A

Same shape
Double membrane
-etc. enzymes in inner membrane
Mitochondrial DNA is similar in sequence to gram negative DNA
-FTSz-like gene
- genes that code for 70s ribo. Like sequence

46
Q

What is taxonomy ?

A

1) classification
2) nomenclature
3) identification (new and previously known species)

47
Q

What are some of the classical taxonomy?

A 
Cell wall type
Shape
O2 regulation
Temp. Regulation
Biochem
48
Q

What are some of the molecular taxonomy?

A

Sequence DNA

- proteins
- RNA
49
Q

What are the 3 ways to tell how closely relatives various bacteria are

A

1) genome sequencing
2) percent G-C content
3) 16S rRNA sequencing

50
Q

What is genome sequencing

A

1) Full sequence coverage of genome
2) gold standard
3) accurate and precise
4) need pure starting point, is expensive

51
Q

What is percent G-C content

A

%G-C = G+C/G+C+A+T

Fast, bur doesn’t hide rich, detailed data sets

52
Q

What is 16S rRNA sequencing

A

1) can be used to identify many different bacteria in a complex sample
2) can help diagnose infections
3) popular, easy, rapid

53
Q

What are archaea-methanogens

A

1) strict anaerobes
2) obtain energy through conversion of: H2 + CO2 -> CH4(methane)
3) one of the largest groups of archaea

54
Q

Where is archaea-methanogens

A

Found in swamps, digestive System of cattle

55
Q

When archaea-methanogens is released

A

Released during melting of permafrost

56
Q

What temp is archaea-thermophiles

A

60-80C

57
Q

What temp is hyperthermophiles

A

> 80C

58
Q

What Are archaea thermophile dependent on(many)

A

Many are sulfur dependent

- obtain energy from sulfur or use it as electron acceptor

59
Q

Where are archaea-thermophiles found

A

Found near deep sea hydrothermal vents, hot springs, etc.

60
Q

When and who was hydrothermal vent discovered

Where are they located

A

Discovered in 1977 by ALVIN

Located in continental fracture zones

61
Q

Why are proline live at high temperatures

A

They are more rigid and they are tougher to denature

62
Q

What are archaea-halophiles

A

They require extremely high salt concentration

At least 1.5 M NaCL, optimum 2-4 M NaCL

63
Q

Where are archaea-halophiles found

A

In salt lakes, evaporation pools, etc.

64
Q

What are archaea-halophiles are often colored with various pigments

A

1) photosynthesis
2) power pumps in the cell
3) protect from UV light damage

65
Q

What are some examples of gram negative bacteria (3)

A

1) enteric bacteria
2) Psrudomonads
3) Rhizobium

66
Q

What are enteric bacteria

A

Gran negative
Many are human pathogens
Often live in the guts of warm(and some cold) blooded animals

Escherichia, salmonella, proteus, enterobacter

67
Q

What are Pseudomonads

A

Gram negative
Opportunistic pathogens of humans and plants
Produce non-photosynthetic pigments
Resistant to antibiotics and form biofilms
- hard to treat

68
Q

What are rhizobium

A

Gram negative

Help form/live in foot nodules of legumes(peas, beans, soybeans)

Harvest N2 gas and convert it to ammonia(NH3)

NH3 is a biologically available form of nitrogen that can be used for amino acids

69
Q

What are examples of gram positive bacteria (4)

A

Streptococci

2) staphylococci
3) clostridia
4) bacilli

70
Q

What is streptococci

A

Typically arranged in chains

2) many are pathogenic
3) some are used in food production(eg. buttermilk)

71
Q

What is staphylococci

A

Often forms clumps

Some are commensals, some are pathogens

72
Q

What is clostridia

A

Strict anaerobes
Form spores

(Botulism, latanus, gamgrene)

73
Q

What is bacilli

A

Diverse genus of bacteria

2) bacillus subtillis(harmless)
3) bacillus thuringiensis (organic pesiside, produces toxic harmless to us but deadly to catipillars)
4) ballicus antracis(causes anthrax)

74
Q

What is chlamydia

A

Neither gram neg. or pos.
Have outer membrane, may/may not have peptidoglycan

Possibly energy parasites (can’t make their own ATP)

75
Q

What is Cyanobacteria

A

Niether gram pos. Or neg.

One of the largest and most diverse groups of bacteria

Makes their own sugars, produce O2 as waste

76
Q

What is development?

A

Increase in specialization of an organism, usually accompanied by an increase in complexity
Eg. fertilization and development in humans

77
Q

How is development in bacteria different?

A

1) usually triggered by changes in environment
2) leads to an increased ability to cope with environment
3) allows specific part of life cycle to be completed
4) does not necessarily lead to an increase in complexity

78
Q

How do bacteria utilize development as a survival strategy?

A

1) form a resistant, metabolic-resting state cell (eg. Endospores)
2) form cells that allow part of life cycle to be completed
3) form cells that maximize ability to disperse(eg. Mycobacteria)

79
Q

What are the 3 types of bacterial development

A

1) differentiation
2) morphagenesis
3) cell-cell interactions

80
Q

What is differentiation bacterial development

A

1 cell type reproduces and forms a variety of different cell types

81
Q

What is morphgenesis bacterial development

A

Conversion of one cell type to another(non-reproductive)

82
Q

What is cell-cell interactions in bacterial development

A

Bacteria coordinate activities for a common purpose(physical and chemical communication)

83
Q

What are the elementary bodies in chlamydia

A
  • infectious bc they can be attached to host cell
  • survive in extracellular environment
  • tough cell wall
  • nonreprouctive
84
Q

What are the reticulate bodies in chlamydia

A
  • non-infectious
  • survive intracellulairky
  • reproduce
85
Q 
Mycobacteria = TB
Mycoplasmic = pneumonia
Myxobacteria = non-pathegenous
A

Know this

86
Q

What is the endospore formation

A
  • formed due to lack of nutrients
  • formed within mother cell
  • resistant to harsh conditions(boil & freeze) (desiccate(dry) & expose to UV light)
87
Q

How do the endospore formation survive

A

Temp-water is removed from spore, no hydrolysis

UV-DNA is protected by binding proteins

88
Q

Why are endospore clinically important?

A

They are difficult to kill

  • resistant to heat & chemical treatment
  • many routines disinfectants do not easily kill endospores
  • need stronger disinfectants
89
Q

What is the heterocysts formation (anabaena) ?

A
  • they are Cyanobacteria
  • chains are composed of normal photosynthesis vegatative cells and specialized cells that fix nitrogen called heterosysts
  • heterocysts have unique structures bc the nitrogen fixation process is oxygen sensitive
    - no photosynthesis
    - thick cell walls that limit O2 diffusion
90
Q

What are the 2 primary types of motility

A

Swimming & gliding

91
Q

What is swimming motility?

A

Most common
Use flagella to propel through liquid medium
- external flagella (blood or water)
- internal flagella-spirochetes (viscous liquid or between cells)

92
Q

What is gliding motility

A

Glide along solid surfaces over secreted slime

Wave of contractions of cytoplasmic filaments propels bacteria forward

93
Q

What are the flagella of spirochetes (3)

A

1) Borrelia bergdorferi
2) treponema pallidum
3) leptospira

94
Q

How do bacteria move: the structure of the flagellum

A
  • acts like a propeller-filament rotation
  • 3 parts filament, hook and basal body
  • self-assembles
95
Q

Why do bacteria move?

A

1) purposeful movement = tactic behavior
2) chemotaxis(most common) = moving towards a nutrient or away from a repellent
3) phototaxis= swimming towards optimal light conditions
4) magnetotaxis= bacteria align wirh magnetic field to find optimal nutrient conditions

96
Q

What are the 2 types of chemotaxis

A

Run and tumble

97
Q

What is run chemotaxis

A

Flagella rotate counter clockwise because high nutrients

A lot of nutrients=a lot more methylation which makes counter clockwise

98
Q

What is the tumble chemotaxis

A

Flagella rotate clockwise because lower nutrients

Lower nutrients = less methylation = clockwise

99
Q

What is metabolism

A

Total of all the chemical reactions in a cell

100
Q

What is catabolism

A

Process where large complex molecules are broken down into smaller ones releasing energy

101
Q

What is anabolism

A

Synthesis of complex macromolecules

102
Q

Why does the hydrolysis of ATP release energy

A

1) relieve of charge-charge repulsion

2) increases entropy

103
Q

ATP hydrolysis is coupled to an u favorable reaction therefore ..

A

The driving the unfavorable reaction forward

104
Q

What are some activities that utilize ATP

A

Biosynthesis (fatty acids, peptidoglycan)

Modify enzymes(group transfer) - active and deactivate

105
Q

What is the core of catabolic metabolism

A

Glucose —> glycolysis —> Krebs cycle —> electron transport chain

106
Q

What happens in glycolysis

A

Glucose —> 2 pyruvate & also 2 ATP and 2 NADH

107
Q

What happens in Krebs cycle

A

Pyruvate —> acetyl CoA —> CO2 And also 2 ATP , 6 NADH , 2 FADH2

More NADH than glycolysis

108
Q

What is anaerobic metabolism

A

Functions without O2
Not as many protons are pumped across during the ATC
It starts wirh glucose or any other organic fuel

109
Q

What is denitrification

A

Additional steps of anaerobic metabolism that further reduce nitrite to other nitrogenous compounds

This allows more protons to be pumped

Important part of nitrogen cycle

110
Q

What is bacterial fermentation

A

Incomplete oxidation of glucose usually preformed in absence of oxygen

Microbiology (4 decks)

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