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Flashcards in Microbial Growth Deck (31):
1

What is microbial growth?

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

2

What is a microbial colony?

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

3

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

Circular, Rhizoid, Irregular, Filamentous and Spindle

4

There can be different margins to microbial colonies. List six

Entire, Undulate, Lobate, Curled, Rhizoid and Filamentous

5

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

Flat, raised, convex, pulvinate and umbonate

6

What are the four methods of reproduction in prokaryotes?

Budding, binary fission, conidiospores and fragmentation of filaments

7

Explain the overview of mitosis.

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

8

What is the generation time?

The time required for a cell to divide

9

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

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

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generation time

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generation time

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gen time

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21

What are the four phases of growth?

Lag phase, log phase, stationary phase and death phase

22

What happens in the lag phase?

The number of cells changes very little

23

What happens in the log phase?

The cells divide and enter a period of growth

24

What happens in the stationary phase?

The growth rate slows

25

What happens in the death phase?

The number of deaths exceeds the number of new cells

26

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

Physical requirements and chemical requirements

27

List three physical requirements bacteria rely on

Temperature, pH and osmotic pressure

28

List some chemical requirements bacteria require

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

29

What are psychrophiles?

Cold loving microbes

30

What are mesophiles?

Moderate temperature loving microbes

31

What are thermophiles?

Heat loving microbes