Chapter 6 Microbial Growth

Question 1

What are the physical requirements for microbial growth?

Answer 1

Temperature, pH, osmotic pressure

Question 2

What are the chemical requirements for microbial growth?

Answer 2

Sources of carbon, nitrogen, sulfur, phosphorus, oxygen, trace elements and organic growth factors

Question 3

Psychorophiles

Answer 3

Cold loving microbes
0-15 degrees Celsius optimal growth
Ocean depths or certain polar regions

Question 4

Psychrotrophs

Answer 4

Cold loving microbes
0 & 20-30 degrees Celsius optimal growth
Cause food spoilage

Question 5

Mesophiles

Answer 5

Moderate temperature loving microbes
(Human honey temperature)
25-40 degrees Celsius optimal growth
Most common spoilage and disease organisms

Question 6

Thermophiles

Answer 6

Heat loving microbes
50-60 degrees Celsius
Found in hot springs and organic compost

Question 7

Hyperthermophiles

Answer 7

Extreme thermophiles
80 degrees or higher optimal growth
Volcanic activity

Question 8

Minimum growth

Answer 8

Lowest Temperature species will grow

Question 9

Optimum growth

Answer 9

Temperature species grows best

Question 10

Maximum growth

Answer 10

Highest temperature at which growth is possible

Question 11

Most bacteria grow best in a narrow range of pH neutrality at a pH of..

Answer 11

pH 6.5-7.5

Question 12

Acidophile

Answer 12

Bacterium that frowns below pH 4. Grows in acidic environments

Question 13

Mold and yeast grown between a pH of…

Answer 13

pH 5-6

Question 14

High osmotic pressure have the effect of…

Answer 14

Removing necessary water from a cell

Question 15

Hypertonic environments ( higher in solutes than inside the cell) cause..

Answer 15

Plasmolysis due to high osmotic pressure

Question 16

Obligate halophiles require

Answer 16

High osmotic pressure (high salt)

Question 17

Facultative halophiles

Answer 17

Tolerate high osmotic pressure (do not require high salt concentration but are able to grow at salt concentration)

Question 18

Cytolysis occurs when a cell

Answer 18

Burst due to an osmotic imbalance that has cause excess water to move INTO the cell

Question 19

Plasmolysis is the process in which cells

Answer 19

Lose water in hypertonic solution, plasma membrane pulls away from cell wall

Question 20

Chemoheterotrophs

Answer 20

Get their carbon from source of their energy (ex protein, carbohydrates and lipids)

Question 21

Chemoautotrophs and photoautotrophs get their carbon from

Answer 21

CO2