Microbial Growth and It's Control

Question 1

increase in number not size

Answer 1

Microbial Growth

Question 2

Enumerate the process of Bianry Fissions

Answer 2

1. Cell elongate and DNA is replicated
2. Plasma Membrane begins to construct and new wall is made
3. Cross-wall forms, completely separating the two DNA copies.
4. Cell separate

Question 3

time required for a cell to divide (and its population to double)

Answer 3

Generation time

Question 4

What are the phases of growth of bacteria

Answer 4

Lag Phase
Log Phase
Stationary Phase
Death Phase

Question 5

Intense activity preparing for population growth, but no increase in population

Answer 5

Lag Phase

Question 6

Logarithmic, or exponential, increase in population

Answer 6

Log Phase

Question 7

Period of equilibrium; microbial deaths balance production of new cells

Answer 7

Stationary Phase

Question 8

Population is decreasing at a logarithmic rate

Answer 8

Deathphase

Question 9

What are requirement for microbial growth for PHYSICAL REQUIREMENT

Answer 9

Temperature
pH
Osmotic pressure

Question 10

What are requirement for microbial growth for CHEMICAL REQUIREMENT

Answer 10

C
N, S, P
Trace Elements
O2
Orgranic growth factors

Question 11

What is the rate of growth of microbial with a temperature of -10 to 20 Celsius

Answer 11

Psychrophiles

Question 12

What is the rate of growth of microbial with a temperature of 0 to 30 degree Celsius

Answer 12

Psychrotrophs

Question 13

What is the rate of growth of microbial with a temperature of 10 to 50 degree Celsius

Answer 13

Mesophiles

Question 14

What is the rate of growth of microbial with a temperature of 40 to 70 degree Celsius

Answer 14

Thermophiles

Question 15

What is the rate of growth of microbial with a temperature of 70 to 110 degree Celsius

Answer 15

Hyperthermophiles

Question 16

Temperatures in this range destroy most microbes, although lower temperatures take more time

Answer 16

70 to 130 degree celsius or 160 to 260 Fahrenheit

Question 17

Very slow bacterial growth

Answer 17

50 to 60 degree celsius or 120 to 140 Fahrenheit

Question 18

Rapid growth of bacteria; some may produce twins

Answer 18

20 to 50 degree celsius or 60 to 120 Fahrenheit

Question 19

Many bacteria survive; some may grow

Answer 19

5 to15 degree celsius or 40 to 60 Fahrenheit

Question 20

Refrigerator tempratures; may allow slow growth of spoilage of bacteria, very few pathogens

Answer 20

0 to 5 degree celsius or 10 to 40 Fahrenheit

Question 21

No significant growth below freezing

Answer 21

-30 to 0 degree celsius or -20 Fahrenheit to 10 Fahrenheit

Question 22

What is the pH of most Bacteria

Answer 22

6.5-7.5

Question 23

even up to 1 pH

Answer 23

acidophiles

Question 24

wider range, usually 5 - 6 pH

Answer 24

Fungi

Question 25

What is used when cultured bacteria produce acids that inhibit growth?

Answer 25

Buffers

Question 26

Hypertonic

Answer 26

High osmotic pressure

Question 27

Hypotonic

Answer 27

Low osmotic pressure

Question 28

Swelling

Answer 28

Low osmotic pressure

Question 29

Plasmolysis (shrinkage)

Answer 29

High osmotic pressure

Question 30

Adding salt can presrve food

Answer 30

High osmotic pressure

Question 31

Can grow at high sal concentrations

Answer 31

Extreme halophiles

Question 32

Under these conditions, the solute concentration in the cell is equivalent to a solute concentration of 0.85% sodium chloride (NaCl).

Answer 32

Cell in isotonic solution

Question 33

If the concentration of solutes such as NaCl is higher in the surrounding medium than in the cell (the environment is hypertonic), water tends to leave the cell. Growth of the cell is inhibited.

Answer 33

Plasmolyzed cell in hypertonic solution