Microbial Growth

Question 1

What is microbial growth?

Answer 1

An increase in the number of cells, not the size of the cells

Question 2

What is a microbial colony?

Answer 2

Groups of cells (large enough to be seen without a microscope) of hundreds of thousands of cells, or populations of billions of cells

Question 3

There can be different shapes to microbial colonies. List five.

Answer 3

Circular, Rhizoid, Irregular, Filamentous and Spindle

Question 4

There can be different margins to microbial colonies. List six

Answer 4

Entire, Undulate, Lobate, Curled, Rhizoid and Filamentous

Question 5

There can be different elevations to microbial colonies. List five.

Answer 5

Flat, raised, convex, pulvinate and umbonate

Question 6

What are the four methods of reproduction in prokaryotes?

Answer 6

Budding, binary fission, conidiospores and fragmentation of filaments

Question 7

Explain the overview of mitosis.

Answer 7

The cell elongates and the DNA is replicated
The cell wall and plasma membrane begin to constrict
A cross-wall forms, completely separating the two DNA copies
The cell separates

Question 8

What is the generation time?

Answer 8

The time required for a cell to divide

Question 9

The generation time varies among organisms, what does it depend on and how long can it take?

Answer 9

The generation time depends on environmental conditions. It is between 1-3 hours for most bacteria but others might require more than 24 hours

Question 10

generation time

Answer 10

h

Question 11

generation time

Answer 11

h

Question 12

gen time

Answer 12

h

Question 13

e

Answer 13

h

Question 14

hh

Answer 14

h

Question 15

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Answer 15

h

Question 16

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Answer 16

h

Question 17

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Answer 17

h

Question 18

hh

Answer 18

h

Question 19

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Answer 19

h

Question 20

h

Answer 20

h

Question 21

What are the four phases of growth?

Answer 21

Lag phase, log phase, stationary phase and death phase

Question 22

What happens in the lag phase?

Answer 22

The number of cells changes very little

Question 23

What happens in the log phase?

Answer 23

The cells divide and enter a period of growth

Question 24

What happens in the stationary phase?

Answer 24

The growth rate slows

Question 25

What happens in the death phase?

Answer 25

The number of deaths exceeds the number of new cells

Question 26

The requirements of growth split into two categories what are these?

Answer 26

Physical requirements and chemical requirements

Question 27

List three physical requirements bacteria rely on

Answer 27

Temperature, pH and osmotic pressure

Question 28

List some chemical requirements bacteria require

Answer 28

Carbon, nitrogen, sulphur, phosphorous, trace elements, oxygen and organic growth factors

Question 29

What are psychrophiles?

Answer 29

Cold loving microbes

Question 30

What are mesophiles?

Answer 30

Moderate temperature loving microbes

Question 31

What are thermophiles?

Answer 31

Heat loving microbes