Effects of Environment on Microorganisms

Question 1

Each organism has a ____ within which growth is possible, and most have well defined _____

Answer 1

• pH range
• pH optima

Question 2

Most natural environments have pH values between ______, and most organisms have pH optima in this range.

Answer 2

5 to 9

Question 3

Very few species can grow at pH values ____ or _____

Answer 3

• below 2
• above 10

Question 4

The very few species that can grow at pH values below 2 or above 10.

Answer 4

• Acidophiles
• Alkaliphiles

Question 5

As temperature rises, chemical and enzymatic reactions proceed at a _____ rate, and the growth rate ____

Answer 5

• faster
• increases

Question 6

Above a certain temperature, _____ are irreversibly damaged.

Answer 6

proteins

Question 7

Above a certain temperature, proteins are?

Answer 7

irreversibly damaged.

Question 8

As temperature is increased within a certain range therefore, growth and metabolic activity increases up to a point where _____ set in

Answer 8

inactivation reactions

Question 9

As temperature is increased within a certain range therefore, _____ and _______ increases up to a point where inactivation reactions set in

Answer 9

• growth
• metabolic activity

Question 10

Above this temperature, cell functions fall sharply to?

Answer 10

zero

Question 11

Above this temperature, they fall sharply to zero.

Answer 11

Cell functions

Question 12

Temperature classes of microorganisms

Answer 12

1. Psychrophiles
2. Mesophiles
3. Thermophiles
4. Hyperthermophiles

Question 13

They have low temperature optima.

Answer 13

Psychrophiles

Question 14

These have midrange temperature optima.

Answer 14

Mesophiles

Question 15

These have high temperature optima.

Answer 15

Thermophiles

Question 16

These have very high temperature optima

Answer 16

Hyperthermophiles

Question 17

Temperature growth rate range of Psychrophiles.

Answer 17

0 to 20 degrees Celsius

Question 18

Temperature growth rate range of Mesophiles.

Answer 18

15 to 45 degrees celsius

Question 19

Temperature growth rate range of Thermophiles.

Answer 19

40 to 70 degrees Celsius

Question 20

Temperature growth rate range of Hyperthermophiles like Thermococcus celer.

Answer 20

65 - 95 degrees Celsius

Question 21

Temperature growth rate range of Hyperthermophiles like Pyrodictium brockli.

Answer 21

80 to 120 degrees celsius

Question 22

Example of Pyschrophile.

Answer 22

Flavobacterium sp.

Question 23

Flavobacterium is an example of what class of microorganism based on temperature?

Answer 23

Psychrophiles

Question 24

Example of Thermophile.

Answer 24

Bacillus stearothermophilus

Question 25

Bacillus stearothermophilus is an example of what class of microorganism based on temperature?

Answer 25

Thermophiles

Question 26

Examples of Hyperthermophiles

Answer 26

- Thermococcus celer - Pyrodictium brockli

Question 27

Classes of microbes in terms of oxygen needs and tolerance.

Answer 27

1. Aerobes 2. Microaerophiles 3. Facultative organisms 4. Anaerobes

Question 28

They are capable of growing at full oxygen tension, and many can tolerate elevated levels of oxygen (greater than 21 %)

Answer 28

Aerobes

Question 29

Aerobes can tolerate elevated levels of oxygen (greater than ___)

Answer 29

greater than 21%

Question 30

They are aerobes that can use oxygen only if it is present at reduced levels in air.

Answer 30

Microaerophiles

Question 31

They are those that under appropriate nutrient and culture conditions can grow in either aerobic or anaerobic conditions.

Answer 31

Facultative organisms

Question 32

They are those organisms that lack respiratory systems and thus cannot use oxygen as the final electron acceptor,

Answer 32

Anaerobes

Question 33

2 Types of Anaerobes

Answer 33

1. Aerotolerant anaerobes 2. Obligate anaerobes

Question 34

They are those organisms which can tolerate oxygen and grow in its presence even though they cannot use it.

Answer 34

Aerotolerant anaerobes

Question 35

They are types of anaerobes that are killed by oxygen

Answer 35

Obligate anaerobes

Question 36

They are unable to detoxify some of the byproducts of oxygen metabolism.

Answer 36

Obligate anaerobes

Question 37

They have enzymes that decompose toxic oxygen products.

Answer 37

Aerobes

Question 38

They lack enzymes that decompose toxic oxygen products.

Answer 38

Anaerobes

Question 39

Methods for determining oxygen need/tolerance

Answer 39

1. Shake culture 2. Paraffin-plug technique 3. Thioglycollate medium thioglycollate 4. O-F test

Question 40

A method for isolating anaerobic bacteria by shaking a deep liquid culture of an agar or gelatin to distribute the inoculum before solidification of the medium.

Answer 40

Shake culture

Question 41

A method of isolating anaerobic bacteria by oxygen deprivation.

Answer 41

Paraffin-plug technique

Question 42

It is for isolation of strict anaerobes.

Answer 42

Thioglycollate medium thioglycollate

Question 43

Its oxygen levels throughout the media is reduced, which is inversely proportional to the distance from the surface (from reaction with it)

Answer 43

Thioglycollate medium thioglycollate

Question 44

Oxidation/ Fermentation Test

Answer 44

O-F test

Question 45

It uses Bromothymol blue as pH indicator

Answer 45

O-F Test