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Microbio > Ch 5 > Flashcards

Ch 5 Flashcards

(59 cards)

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1
Q

Peptidoglycan

A

Sting mesh like material found only in bacteria interconnected glycan chains form a large sheet
Alternating series of subunits form glycan chains
N acetylmuramic acid NAM
N acetylglucusamine NAG
Tetrapeptide chain string of four amino acids links glycan chains
Gram positive cells have peptide Interbridge between tetra peptide chains

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2
Q

Bacteria growth

A

Increases in number not in cells size
Bacteria grow by dividing via binary fission
Exponential growth

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3
Q

Generation time

A

Time required for a cell to divide/double
Can be thought of as how long it takes to double
Varies for each microorganism

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4
Q

Principles of bacteria

A

Binary fission leads to exponential growth
2^n

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5
Q

Bacteria growth in nature

A

Planktonic: single cells
Biofilms: bacterial communities
Polysaccharide encased communities
Form slime
Adhere to surface

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6
Q

Benefits of biofilms bacteria

A

Share nutrients
Shelter bacteria from harmful factors like our immune system and medications
Cells sense changes each other adjust to surroundings
Synthesize compounds useful for growth
To humans, it can beneficial to us through bioremediation

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7
Q

Bacteria grows as biofilms

A

Is polysaccharide encased communities
Can act as a shelter cells are more protected

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8
Q

Bacteria growth in nature

A

Prokaryotes regularly grow in close association
Many different species
Interactions can be cooperative: can fostered growth of species otherwise unable to survive
Interactions can be competitive:some synthesize toxic compounds to inhibit competitors

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9
Q

Biofilms have important implications

A

70% of human infections are caused by biofilms. Industrial concerns:accumulations in pipes/drains

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10
Q

Biofilms benefits to bacteria

A

Share nutrients via channels
Shelter bacteria from harm (immune systems, antibiotics)

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11
Q

Inoculate

A

Introduce microbes into a medium

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12
Q

Culture

A

Microbes growing in or on medium

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13
Q

Pure culture

A

Microbes from one species/strain

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14
Q

Culture medium

A

Nutrients for microbial growth

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15
Q

Agar

A

Solid form of media
Look for isolated colonies

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16
Q

Broth

A

Liquid form of media
Look for tubidity= cloudiness of the culture

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17
Q

The growth curve

A

Bacteria are inoculated into a medium in lab. You see a bacterial growth curve.
Growth curves can show the growth of bacteria overtime
Growth curve are represented logarithmically

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18
Q

Four main phases of the growth curve

A

Lagged face, log face, stationary face, death face

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19
Q

Lag face

A

Little bacteria, division, as bacteria, adjust to new, medium, high metabolism, or metabolically active cells

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20
Q

Log phase

A

Exponential growth increase in bacteria population high cell division

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21
Q

Stationary phase

A

Rate of bacteria, growth/division equals rate of bacterial death

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22
Q

Death phase

A

High death of bacteria, due to lack of nutrients and toxic by products

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23
Q

Requirements for a microbial growth

A

Prokaryotes inhibit nearly all environment
Some live comfortable in habitats favored by humans

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24
Q

Extremophiles

Study These Flashcards
A

Harsh environment prokaryotes:most are archaea

25
Environmental requirements for microbial growth
Temperature PH osmotic, pressure and oxygen
26
Nutritional requirements for microbial growth
Carbon, nitrogen, sulfur, and phosphorus, and trace elements
27
Psychrotrophs/pyschrophiles
Cold, loving loving optimal temperature equals 10 c Cause food spoilage in the refrigerator
28
Mesophiles
Moderate temperature loving optimal temperature equals 37C
29
Thermophiles
Heat loving optimal temperature equals 60 c
30
Hyperthermophiles
Superheat, loving optimal, temperature 95C
31
PH
Most bacteria grow within a pH of 6.5 and 7.5. Neutrophils ph 6-8 Acidophilus ph<5.5 Alkaliphiles ph>8.5
32
Osmotic pressure water availability
Isotonic solution equals no net movement of water particles. The cell membrane is attached to cell wall. Hypertonic solution equals water particles move out of the cell, the cell membrane, it shrinks and detaches from cell wall Hypotonic solution water particles move into the cell cell wall, counteracts osmotic pressure to prevent swelling and lysis
33
Hypertonic environment
The cell wall of the bacteria usually protects itself to keep it from bursting High salt environments
34
Plasmolysis
Cell lose water take and shrink up and die the fluid moves out of the cell
35
Facultative halophiles
Tolerate high osmotic pressure so they are not killed by salt
36
Obligate aerobes
Require oxygen for respiration and have enzymes to help with oxygen toxic by products, such as catalase and super oxide dismutase
37
Obligate anaerobes
Killed by oxygen, only girl with no oxygen
38
Facultative anaerobes
Grow by anaerobic respiration, when oxygen is present but grow via fermentation or anaerobic respiration when oxygen is not available
39
Aerotolerant anaerobes
Tolerate oxygen, but cannot use oxygen
40
Microaerophilles
Require low, oxygen concentration
41
Bacteria require major elements, and trace elements needed for growth
Carbon, part of all macromolecules of cells is a major energy source
42
Heterotrophs
organic carbon sources most microbes need food
43
Autotrophs
Use of CO2 and inorganic carbon source Photo synthetic microbes
44
Nitrogen
Component of proteins Component of DNA,RNA and ATP
45
Phosphorus
Component of DNA,RNA and ATP Found a phospholipid cell membranes
46
Sulfur
Found in amino acids, thiamine, and biotin Most bacteria, decompose proteins for the sulfur source
47
Trace elements
Inorganic elements required and very small amounts, such as iron, zinc, copper, potassium, magnesium calcium cobalt manganese these are usually enzyme cofactors
48
Hundreds of types of my growth media available
Some medically, important microbes, and most environmental ones have not been grown in lab
49
MacConkey agar media
A type of selective and differential media MacConkey agar is a selective media used to isolate Graham negative bacteria from a culture contains a die and bile salts that inhibit the growth of gram-positive bacteria It is also a differential media because it contains lactose in a pH indicator
50
Selective media
Contains ingredient, that inhibit the growth of certain species while allowing the growth of other species
51
Differential media
Contain a substance that specific microbes change in a recognizable way
52
MacConkey agar. Is a differential media because it contains lactose.
Material that ferment lactose produce lactic acid The acid turn the pH indicator, pink red colonies that ferment lactose and pure pink red Colonies, that don’t ferment lactose a colorless
53
LB agar plate
Nonselective culture media Use for bacterial cultures Nutrient, rich Knigge used to grow enteric, intestinal species of bacteria Will gro, a lot of different species of a Commonly used for E. coli Contains proteins, used salt and agar
54
Direct cell counts
Total numbers living plus dead
55
Message to detect and measure microbial growth, : viable plate count
Count the number of cells capable of multiplying
56
Colony equals colony forming units CSU
Take 1 mL of your samples Dilute the sample through a series of dilutions called serial dilution As you dilute, the number of bacteria progressively decreases Play some sample for me to solution into an agar plate to grow Incubate the plates Count the bacterial colonies in each plate in the various solutions to determine the number of valuable bacteria in the original 1 mL sample 
57
Play Tacones
Single soul gives rise to one colony 30-300 as ideal 
58
Membrane filtration
Concentrates microbes by filtration Filter is incubated, on appropriate, agar, medium
59
Measuring biomass
Optical density turbidity is proportional to concentration of cells 1OD=5x10^8 cells/ml measure with spectrophotometer absorbents at 600 nm 

Microbio (12 decks)

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