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BIOL > Microbial Growth And Control (Lec 6-7) > Flashcards

Microbial Growth And Control (Lec 6-7) Flashcards

1
Q

Bacterial Growth

A

Increasing the # of cells

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2
Q

Binary Fission

A

Cell division following enlargement of cell to 2x it’s normal size

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3
Q

Generation Time

A

Time it takes to double cell population

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4
Q

Peptidoglycan Biosynthesis

A

Production of new cell wall material

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5
Q

Cocci cell wall synthesis

A

Wall grows in opposite directions outward of the FtsZ ring

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6
Q

Rod-shaped cell wall biosynthesis

A

Wall grows at several points along the cell

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7
Q

Autolysins

A

Creates small openings in the wall which new cell material is added across

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8
Q

Bactoprenol

A

C55 alcohol that is large enough to transport sugar peptidoglycan across the cell membrane

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9
Q

Glycolase

A
  • Enzyme that interacts with bactoprenol to insert cell wall precursors into the growing points
  • Catalyzes glycosidic bond formation
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10
Q

Transpeptidation

A
  • Final step in cell wall synthesis
  • Forms peptide cross-links between glycan chains
  • Inhibited by antibiotic penicillin
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11
Q

Peptidoglycan elongation

A

MreB organizes the elongasome

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12
Q

MreB

A
  • forms simple cytoskeleton bands around the cell under the membrane in bacteria and probably archaea
  • directs cell wall synthesis to specific points along the rod-shaped cell
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13
Q

Elongasome

A

Protein that helps elongate/form the rod shape of some bacterias

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14
Q

Divisome

A
  • Squeezes and divides cell at FtsZ ring during division
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15
Q

FtsZ Ring

A
  • Forms ring around center of cell the divisome can build from
  • location determined by Min Proteins
  • DNA replicates before ring forms
  • related to tublulin (a protein responsible for cell structure and microtubules)
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16
Q

Exponential Growth

A
  • growth starts slow and becomes faster
  • growth of microbial population where cell numbers double in a specific time
  • N = No2^n
    N = final # No = initial # n = generation #
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17
Q

Batch Culture

A
  • Closed-system of microbial culture with fixed volume
  • Lag phase, Exponential phase, Stationary phase, Death phase
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18
Q

Lag phase

A
  • To keep culture from dying keep in this phase of NO GROWTH
  • freeze or dehydrate colony
  • Time between inoculation of culture and beginning of growth
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19
Q

Why do Cells have to Die?

A

2nd Thermo law: energy becomes more disorganized

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20
Q

Exponential phase

A

Cells in this phase are typically healthiest

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21
Q

Stationary Phase

A

Cell population growth is zero

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22
Q

Death phase

A

If incubation continues after stationary phase the cells will die

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23
Q

Continuous Culture

A
  • Open-system of microbial culture of fixed volume
  • Chemostat: most common device
    -Controls growth rate by dilution rate
    -Controls growth yield by concentration of limiting nutrient
24
Q

Growth Rate

A

How much colony grows determined by dilution rate: (rate which new growth medium pumped in and spent out)

25
Q

Growth Yield

A

Population density (cell # / mL) controlled by limiting nutrient.

26
Q

Cytometer

A

-counts cells in liquid samples
-uses lasers, fluorescent dyes, and electronics

27
Q

Viable Cell Counts

A

-Measures living, reproducing cell population
-Use serial dilutions to make plate counts
-Can be unreliable bc growth medium is good for some bacteria and bad for others

28
Q

Spectrophotometry

A
  • measures turbidity through light absorption called Optical Density (OD)
  • standard curve must be established
  • sometimes clumps of biofilms formed by microbes can be problematic
29
Q

Cardinal Temperatures

A
  • Min, max, and optimum temperatures for an organism
  • classifies organisms into psychrophile, mesophile, thermophile, and hyperthermophile
30
Q

Pyschrophile

A

Low temp loving

-More flexible a-helices than B-sheets
-High unsaturated fatty acid content
-More polar and strong bonds

31
Q

Mesophile

A

Midrange temp loving

32
Q

Thermophile

A

High temp loving

-critical amino acid substitutions in a few locations provide heat-tolerant folds
- increased # of ionic bonds between basic and acidic amino acids
- produces solutes that stabilize proteins
- bacteria: lipids rich in saturated fatty acids
- archaea: lipid monolayer not bilayer

33
Q

Hyperthermophile

A

Extremly high temp loving

-Produces enzymes widely used in industrial microbiology
-Ex Taq polymerase automates polymerase chain rxn technique

34
Q

Osmolarity effect on growth

A
  • Usually, cytoplasm solute concentration is higher than surroundings so water moves in
  • If low water activity/high solute [ ] of surroundings cell water moves out or pumps solute in
35
Q

Halophiles

A

Grow best with NaCl and reduced water

36
Q

Extreme Halophiles

A

Require high level of NaCl to grow (15-30%)

37
Q

Halotolerant

A

Can tolerate lower water activity, however best in absence of added solute

38
Q

Osmophiles

A

Grow best in high sugar environments

39
Q

Xerophiles

A

Grow in very dry environments

40
Q

Compatible solutes

A

Neutral solutes that can help organisms survive extreme osmotic stress

41
Q

Aerobes

A

Require Oxygen to live

42
Q

Anaerobes

A

Do not require/can be killed by Oxygen
- lots of human pathogens anaerobic

43
Q

Facultative aerobes

A

Can live with or without Oxygen

44
Q

Aerotolerant anaerobes

A

Can grow in Oxygen environments but don’t use it

45
Q

Microaerophiles

A

Use oxygen when it is present at levels reduced from that in air

46
Q

Thioglycolate Broth

A

Medium that separates microbes based on Oxygen requirements

47
Q

Reducing agents

A

Chemicals added to culture media to reduce Oxygen

48
Q

Heat Sterilization

A

Most common method of controlling microbial growth

49
Q

Pasteurization

A

Uses precisely controlled heat to reduce microbes in heat-sensitive liquids (does not kill all organisms)

50
Q

Microwave Radiation

A

Energy from waves hits and damages cells

51
Q

UV Radiation

A

Shorter wavelength higher Energy but penetrates surfaces less

52
Q

Filtration

A

Avoids heat on sensitive liquids/gases however only stops bacteria, not viruses

53
Q

Bacteriostatic

A

-Inhibits growth/no killing
-best for medicine because immune system kills all strains not just those selected for high resistance

54
Q

Bacteriocidal

A
  • Kills cells without lysing
  • If used in medicine will select for resistance
55
Q

Bacteriolytic

A
  • Kills cells with lysing
  • If used in medicine will select for resistance
56
Q

Minimum inhibitory concentration (MIC)

A
  • Smallest amount of an agent needed to inhibit growth
  • Specific to each organism
  • Double [] each test tube when figuring out capacity

BIOL (4 decks)

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