2. Bacterial Nutrition and Growth

Question 1

The requirements for growth

Answer 1

1. Physical
   - Temperature
   - pH
   - Oxygen
   - Osmotic pressure
2. Chemical
   - Carbon
   - Nitrogen, Sulfur & Phosphorus
   - Trace elements
   - Oxygen
   - Organic growth factor

Question 2

Temperature and Microbial Growth

Answer 2

1. Minimum temperature
2. Optimum temperature
3. Maximum temperature

Question 3

Minimum Temperature

Answer 3

temperature below which growth ceases/ lowest temperature at which microbes will grow.

Question 4

Optimum Temperature

Answer 4

Temperature at which its growth rate is the fastest.

Question 5

Maximum Temperature

Answer 5

Temperature above which growth ceases, or highest temperature at which microbes will grow.

Question 6

pH & Microbial growth

Answer 6

Acidophiles : organisms that grow best at low pH (optimum in pH range 1-4)
Alkalophiles : organisms that grow best at high pH (optimum in pH range 8.5-11)

Question 7

Osmotic effect and water activity

Answer 7

1. Osmophiles
2. Osmotolerant
3. Halophiles
4. Halotolerant
5. Barophiles
6. Barotolerant

Question 8

Osmophiles

Answer 8

organisms which thrive in high solute

Question 9

Osmotolerant

Answer 9

organisms which tolerate high solute

Question 10

Halophiles

Answer 10

organisms which thrive in high salt

Question 11

Halotolerant

Answer 11

organisms which tolerate high salt

Question 12

Barophiles

Answer 12

organisms which thrive in high pressure

Question 13

Barotolerant

Answer 13

organisms which tolerate high pressure

Question 14

Oxygen & Microbial growth

Answer 14

1. Aerobes
   - Obligate
   - Facultative
   - Microaerophiles
2. Anaerobes
   - Aerotolerant
   - Obligate
   - Facultative

Question 15

Obligate aerobe

Answer 15

require oxygen to grow

Question 16

Facultative aerobe

Answer 16

can live with or without oxygen but grow better with oxygen

Question 17

Microaerophiles

Answer 17

require reduced level of oxygen

Question 18

Aerotolerant anaerobes

Answer 18

can tolerate oxygen but grow better without oxygen.

Question 19

Obligate anaerobe

Answer 19

• do not require oxygen

- are killed by oxygen

Question 20

Facultative anaerobe

Answer 20

Grow better in oxygen

Question 21

Types of media

Answer 21

1. Physical state
2. Chemical composition
3. Functional type

Question 22

Physical states of media

Answer 22

1. Liquid
2. Semisolid
3. Solid (can be converted into a liquid)
4. Solid (cannot be converted into a liquid)

Question 23

Chemical composition of cultural media

Answer 23

1. Synthetic media

2. Complex/ Non-synthetic media

Question 24

Functional type of cultural media

Answer 24

1. Selective media
2. Differential media
3. Enrichment media

Question 25

Binary fission

Answer 25

1. Cell elongates 2. Cell wall and plasma membrane begin to divide 3. Cross-wall forms completely around divided DNA 4. Cells separate

Question 26

Four major phases of growth in batch culture

Answer 26

1. The lag phase 2. The logarithmic phase 3. The stationary phase 4. The death phase