Microbial Growth

Question 1

Describe the difference between the four major temperature preferences for a living organism

Answer 1

Psychrophiles : icy waters 10-20
Mesophiles: body temp 37-45
Thermophiles: hot springs 60-80
Hyperthermophiles: ocean vents above boiling 90-95

Question 2

Which group of organisms are typically human pathogens

Answer 2

Mesophiles

Question 3

Which class of organisms is the most dangerous for food spoilage

Answer 3

Cold tolerant mesophiles

Question 4

Explain the pH requirements for growth of micro organisms:

Acidophiles

Neutrophiles

Alkaliphiles

Answer 4

Acidophiles: below ph 2.0

Neutrophiles: 6.5-7.5 ph

Alkaliphiles: 8.5-11 ph

Question 5

How does osmotic pressure of them at growth of the micro organism

Answer 5

HiGh salt causes sell to lose water and inhibit the growth

Question 6

What is plasmolysis? And why might this reduce cellular growth?

Answer 6

Concentration of the plasma membrane of a cell due to water loss

Question 7

What is a halophile?

Answer 7

Loves salt

Question 8

Explain the oxygen requirements of the following types of organisms

Obligate aerobes

Obligate anaerobes

Facultative anaerobes

Aerotolerant anaerobes

Microaerophiles

Answer 8

Obligate aerobes:
Must use oxygen cellular respiration

Obligate anaerobes: Must live without oxygen fermentation

Facultative anaerobes: Optional without oxygen

Aerotolerant anaerobes: Without oxygen but tolerant

Microaerphiles: Small amount of oxygen

Question 9

If you ate some thing and got salmonella what type of organism would it be present

Answer 9

Acid tolerant neutrophiles

Question 10

Predict the metabolic and oxygen tolerant characteristics of the following organisms
For an obligate Aerobe

Answer 10

Would it have an electron transport chain

yes

would it have catalase

yes

will it have a super oxide dismutase

yes

what is the final electron acceptor during cellular respiration

oxygen

does it need to use the citric acid cycle to generate energy or wouldn’t rely mostly on glycolysis

citric acid cycle

Question 11

For an obligate anaerobes

Answer 11

Electron transport chain
no

if it has an electron transport chain or the final electron except or B oxygen no and no

if it has an electron transport chain what is the general pathway it would use to generate energy
fermentation

does it have catalase no no does it have super oxide dismutase

no

Question 12

For facultative anaerobes

Prefers oxygen

Answer 12

Does it have an electron transport chain if so what is the electron transport chain spinal electron acceptor

Yes oxygen (cellular respiration 38 ATP / 1 glucose)

Can it carry out fermentation (2 atp /1 glucose)

yes

Does it have catalase and does it have super oxide dismutase
Yes and yes

Question 13

Aerotolerant anaerobes

Answer 13

Does it have an electron transport chain
No

does it use the citric acid cycle
yes

what pathway is most likely to provide the most energy
fermentation

does it have catalase are super oxide dismutase

Yes because it tolerates air

Question 14

Microaerophile

Answer 14

Does it have an electron transport chain
yes

does it use the citric acid cycle
yes

does it have catalase/super oxide dismutase

Yes but week possibly or lack of enzymes

Question 15

Explain why the atmosphere of earth has oxygen in it and why our atmosphere does not resemble that of Mars or Venus

Answer 15

The development of photosynthesis oxygenated earths atmosphere cyanobacteria involved photosynthesis

Question 16

Describe the difference between selective and differential media

Answer 16

Selective media inhibits or kills bacteria you don’t want

differential media mix cultures of bacteria look different on plates and has a pH indicator