biotechnology

Question 1

what are the living organisms most commonly used in biotech?

Answer 1

bacteria & fungi

Question 2

why are bacteria & fungi most commonly used?

Answer 2

• short life cycle = grow rapidly, form products quickly
• ideal growth conditions easily created
• grow at any time of year

Question 3

what is bioremediation?

Answer 3

process of using organisms to remove pollutants from contaminated sites

Question 4

how does bioremediation work?

Answer 4

stimulates growth of suitable microbes that use contaminants as food source

Question 5

describe the conditions required for bioremediation

Answer 5

• water available
• suitable temperature
• suitable pH

Question 6

what modifications are made when bioremediation conditions are not suitable?

Answer 6

• addition of substances such as molasses to provide nutrients for effective growth
• pump oxygen for aerobic bacteria

Question 7

summarise the advantages of bioremediation

Answer 7

• uses natural systems
• less labour/equipment
• few waste products
• less risk of exposure to people from clean ups

Question 8

what is an example of large scale culturing?

Answer 8

fermenter/bioreactor

Question 9

what is an example of small scale culturing?

Answer 9

growing on agar gel using petri dishes

Question 10

what is a culture?

Answer 10

population of one type of micro organism that has been grown under controlled conditions

Question 11

state the 2 main methods for culturing micro organisms

Answer 11

• batch fermentation
• continuous fermentation

Question 12

what is contained in the culture medium?

Answer 12

• water & minerals
• increases product yield because micro organisms can always access nutrients for growth

Question 13

what is the purpose of the paddles in the culture medium?

Answer 13

stops cells settling at the bottom
- allows all micro organisms to access nutrition & oxygen

Question 14

describe the process of batch fermentation

Answer 14

• micro organisms grown in individual batches
• in a fermentation vessel

Question 15

what is the purpose of oxygen supply?

Answer 15

• oxygen volume kept at optimum level for respiration
• pumps sterile air into vessel
• increases product yield because micro organisms can always respire to provide energy for growth

Question 16

what is the purpose of the pH monitoring?

Answer 16

• monitored by pH probe
• increases product yield because enzymes can work efficiently so rate of reaction is high

Question 17

what is the purpose of the water jacket on the fermentation vessel?

Answer 17

• keeps temperature at optimum
• increases product yield because enzymes can work efficiently so rate of reaction is high

Question 18

what is the purpose of sterilising the fermentation vessel?

Answer 18

• uses superheated steam to kill unwanted organisms and ensure next culture is not contaminated
• increases product yield because micro organisms aren’t competing with other organisms

Question 19

describe the process of batch fermenting

Answer 19

• sterilise vessel
• set up culture
• ferment for a week
• do not add nutrients
• do not waste products
• may add O2 - sterile air - if not brewing
• empty vessel, harvest & purify
• set up again
• reach stationery phase as product is a secondary metabolite

Question 20

describe the process of continuous fermentation

Answer 20

• sterilise vessel
• set up culture
• ferment for 5 years unless contaminated
• continuously add nutrients and remove waste products
• continuously add O2 and remove CO2
• continuously harvest & purify products
• keep in log phase / exponential as product is a primary metabolite

Question 21

give an example of batch fermentation

Answer 21

culturing mould to produce penicillin

Question 22

give an example of continuous fermentation

Answer 22

using GM e coli to produce insulin

Question 23

what is meant by ‘secondary metabolite’ ?

Answer 23

only produced once population has reached a certain size