Chapter 6 - Microbial Growth

Question 0

Temperature Range Classifications

Answer 0

• Psychophile [0-(10-15)-30C]
• Mesophile (35-37C) (Pathogens)
• Thermophile (60C)

Question 1

Physical Requirements for Growth

Answer 1

• Temperature
• pH
• Osmotic Pressure

Question 2

Optimum pH Growth

Answer 2

Growth between 5-9
Optimum between 6.5-7.5
Certain molds <4
Acidophiles 4-5

Question 3

Osmotic Bacteria Classification

Answer 3

Extreme (Obligate) Halophiles
- require high solute or osmotic pressure
Facilitative Halophiles
- can tolerate high solute or osmotic pressure

Question 4

Source and Function of Carbon

Answer 4

• Needed for Organic Compounds
• Energy Source
• Chemoheterotrophs use organic sources
• Autotrophs use CO2

Question 5

Chemical Requirements for Growth

Answer 5

Carbon
Nitrogen
Sulfur
Phosphorus
Trace Elements
- (C.HOPKINS CaFe Mighty nice Mighty good) (Cl, Na, Zn)

Question 6

Source and Function of Nitrogen

Answer 6

• Used for Amino Acids and Proteins

- Gained by decomposing proteins or from ammonium and nitrate

Question 7

Source and Function of Sulfur

Answer 7

• used in thiamine and biotin ( Amino Acids)

- Gained from decomposing proteins or from SO4(2-) or H2S

Question 8

Source and Function of Phosphorus

Answer 8

• Used in DNA, RNA, and ATP

- Gained from PO4(3-)

Question 9

Toxic Forms of Oxygen

Answer 9

• Singlet Oxygen (O)
• Superoxide Free Radical
  ~ converted w/ superoxide dismutase
• Peroxide Anion (O2(2-))
• Hydroxyl Radical (OH•)

Question 10

What is an Organic Growth Facter

Answer 10

• An organic compound obtained from the environment because synthesize is unavailable
• E.Coli does not need growth factors

Question 11

Types of Prokaryote Reproduction

Answer 11

• Binary Fission
• Budding
• Condidospores (filament fragmentation)

Question 12

Biofilm

Answer 12

A Microbial Community made of polysaccharides, DNA, and proteins

Question 13

Quorum Sensing

Answer 13

Cell-Cell communication and transportation in a biofilm

Question 14

Generation Time

Answer 14

• The time it takes for the population to double

- 2^g = n (g = generation)

Question 15

Bacterial Growth Graph

Answer 15

• Number of Cells (Exponential)

- Log10 Number of Cells (Linear)

Question 16

Stages of Growth

Answer 16

1. Lag Phase
2. Exponential/Log Phase
3. Stationary Phase
4. Death Phase

Question 17

Lag Phase

Answer 17

• Adjustment phase
• Ribosome synthesis
• No division

Question 18

Exponential/Log Phase

Answer 18

• Minimum generation time
• Maximum rate of division
• Most sensitive to antimicrobials

Question 19

Stationary Phase

Answer 19

• Nutrients begin to run out
• Waste builds up
• Growth slows and equals deaths

Question 20

Death Phase

Answer 20

• Rate of Death > Rate of Growth

Question 21

Direct Measurement Techniques

Answer 21

• Dilution and Plate Count
• Filtration
• Direct Microscopic Count

Question 22

Indirect Measurement Techniques

Answer 22

• Turbidity (cloudiness)