2.6 Environmental Control of Metabolism

Question 1

What are some examples of micro organisms?

Answer 1

Archaea, bacteria and some species of eukaryotes

Question 2

What is an aseptic technique?

Answer 2

A set of practices that protects someone from contamination from a microbe

Question 3

Why do we use aseptic technique?

Answer 3

• To prevent contamination of the microbe we are growing,
• Stop other microbes competing and using up resources and reducing yield.
• To prevent the microbe we are culturing contaminating the environment, it may be harmful to human health

Question 4

What are two methods of aseptic technique?

Answer 4

Computer controlled fermenter and product monitoring

Question 5

What do computer controlled fermenters do?

Answer 5

Grow micro-organisms on a vast scale to produce useful products e.g. Antibiotics

Question 6

What are the four phases of growth?

Answer 6

Lag, log/exponential phase, stationary, death

Question 7

What is the lag phase?

Answer 7

Where enzymes are induced to metabolise substrates

Question 8

What is the log/exponential phase?

Answer 8

This phase contains the most rapid growth of micro-organisms due to plentiful nutrients

Question 9

Why does the stationary phase occur?

Answer 9

due to the nutrients in the culture media becoming depleted and the production of toxic metabolites. Secondary metabolites are also produced such as antibiotics.

Question 10

Why does death stage occur?

Answer 10

Due to the toxic accumulation of metabolites or the lack of nutrients in the culture