Microbial nutrition and growth

Question 1

Microbial environment used to be completely anoxic, what is anoxic

Answer 1

Without oxygen

Question 2

What bacteria caused change in oxygen levels

Answer 2

Cynobacteria
More oxic
More photosynthetic

Question 3

What are examples of energy sources for microbes

Answer 3

Carbon

Nitrogen

Question 4

What do chemoorganotrophs make and why is this useful

Answer 4

Hydrogen used by chemolithotrophs

Question 5

What is a phototroph

Answer 5

Photosynthetic microbes

Question 6

What is a chemotroph

Answer 6

Obtain energy from chemicals

Question 7

What do chemoorganotrophs use

Answer 7

Organic compounds

Question 8

What do chemolithotrophs use

Answer 8

Inorganic compounds

Question 9

What has oxygen as it’s terminal electron acceptor

Answer 9

Aerobe

Question 10

What is an autotroph

Answer 10

Uses carbon dioxide as sole carbon source

Question 11

What is a heterotroph

Answer 11

Uses carbon from complex compounds

Question 12

What examples are there of nutrient types

Answer 12

Macronutrients
Micronutrients
Trace metals
Growth factos
Vitamins

Question 13

What are examples of macronutrients

Answer 13

Carbon
Hydrogen
Oxygen
Nitrogen

Question 14

What are the possible sources of carbon

Answer 14

Carbon dioxide (not all photosynthetic)
From complex compounds

Question 15

What are the possible sources of nitrogen

Answer 15

Gaseous N2 e.g. nitrogen fixing bacteria

Inorganic N e.g. denitrifying bacteria

Question 16

How can other nutrients be taken up into cell

Answer 16

Taken up as trace elements dissolved in water
Some as gases
Some as nutrients actively transported into cell

Question 17

What are the essentials for microorganism growth

Answer 17

Nutrient source
Water
Temperature 
pH
Atmospheric conditions

Question 18

Why is water needed in microorganism growth

Answer 18

Most microorganisms can only absorb soluble chemicals

Rigid cell wall prevents cell bursting

Question 19

What does hypertonic media cause

Answer 19

Cell loses water and shrinks

Question 20

What does hypotonic media cause

Answer 20

Cell swells

Question 21

What (water) environment do most microbes live in

Answer 21

Slightly hypotonic

Question 22

What is an extreme thermophile

Answer 22

Extreme heat loving

Question 23

What is a thermophile

Answer 23

Heat loving

Question 24

What is a mesophile

Answer 24

Middle temperature range

Question 25

What is a psychrophile

Answer 25

Cold loving

Question 26

What is the normal pH range for eubacteria

Answer 26

6-8

Question 27

What is the minimum pH for microbial growth

Answer 27

4

Question 28

What is the maximum pH for microbial growth

Answer 28

9

Question 29

What must the intracellular pH be

Answer 29

Maintained within 2 pH units of neutral (7)

Question 30

How do bacteria survive in low pH

Answer 30

They adjust their intracellular pH in response to changes in extracellular pH

Question 31

What does the cytoplasmic pH have to be

Answer 31

Stay close to neutral

Question 32

What is an obligate aerobe

Answer 32

Requires oxygen

Question 33

What is a facultative aerobe

Answer 33

Doesn't need oxygen, but will use it if there

Question 34

What is a microaerophile

Answer 34

Requires lowered oxygen levels

Question 35

What is an aerotolerant anaerobe

Answer 35

Grows best without oxygen but can tolerate its presence

Question 36

What is a strict anaerobe

Answer 36

Can't tolerate oxygen

Question 37

What are the laboratory conditions for growth

Answer 37

Correct media containing all nutrients and solute concentration Correct incubation temperature Correct atmospheric conditions

Question 38

How is the growth of bacteria and cell division described in a graph

Answer 38

Rate of increase is an exponential function

Question 39

What is binary fission

Answer 39

Transfer of genetic material before septum formation or will not be viable cells

Question 40

What is the lag phase in batch culture growth

Answer 40

Cells initiate growth | Try acclimatise to new environment

Question 41

What is the exponential phase in batch culture growth

Answer 41

Cell number doubles in minimum time

Question 42

What is the stationary phase in batch culture growth

Answer 42

Cell growth slows and eventually stops

Question 43

What is the death phase in batch culture growth

Answer 43

Number of viable cells slowly declines

Question 44

When does growth in batch culture stop

Answer 44

When nutrients limited or a by-product of growth becomes toxic

Question 45

What processes use continuous cultures

Answer 45

Basis of fermentation - making antibiotics - nutrients continually replaced - cell numbers kept constant - toxic metabolic products washed out