20: Biotechnology And Genetic Engineering

Question 1

Define Biotechnology.

Answer 1

The use of bacteria and fungi to produce useful substances or to carry out services for us.

Question 2

How are bacteria useful in biotechnology? List 4 reasons.

Answer 2

• Bacteria reproduce very quickly with a generation time that is often as little as 30 minutes.
• Unlike animals or plants, microbes can convert raw materials into the finished product very quickly, I.e. hours rather than months or weeks.
• The use of bacteria means that food production can be independent in climate.
• Bacteria can produce complex proteins (like enzymes & antibiotics) that pass out into the surrounding medium and can he harvested. Enzymes made by microorganisms are use in the food industry.

Question 3

What is fermentation?

Answer 3

The process in which yeast respires anaerobically (without oxygen).

Question 4

What is the word equation of the anaerobic respiration in yeast?

Answer 4

Glucose —> alcohol + carbon dioxide + energy released

Question 5

Define biofuels.

Answer 5

Biofuels are renewable and carbon neutral (do not give off CO2) as they are fuels produced from natural products, often plant biomass.

Question 6

What can be fermented to produce ethanol?

Answer 6

Sugar rich products such as sugar cane and maize can be fermented anaerobically to produce ethanol.

Question 7

Why is Ethanol seen as a better substitute for petrol?

Answer 7

Ethanol is seen as a better substitute for ethanol because it has a higher energy content and does not produce any toxic gases when burnt. Ethanol is also Carbon neutral.

Question 8

How are food stains broken down by washing powders and list 3 main enzymes that help in the process.

Answer 8

Enzymes in washing powders help to digest these stains so they can be washed away.

Proteases break down proteins into amino acids

Lipase break down fats into fatty acids and glycerol

Carbohydrates breaks down carbohydrates into glucose.

All the simple molecules left are soluble and will dissolve in the water which will then be removed.

Question 9

What is Genetic Engineering?

Answer 9

Changing the genetic material of an organism by removing, changing or inserting individual genes from another organism.

Question 10

List 3 examples of Genetic Engineering.

Answer 10

• Human insulin production
• Herbicide resistance in crop plants
• Insect pest resistance in crop plants

Question 11

What is a plasmid?

Answer 11

Circular DNA found in bacteria

Question 12

What are Restriction Enzymes?

Answer 12

Enzymes used to cut the selected gene and the plasmid.

Question 13

What is DNA ligase?

Answer 13

Enzyme used to paste the selected gene into the plasmid.

Question 14

What is Recombinant Plasmid?

Answer 14

Plasmid with the new gene inserted into it.

Question 15

Thoroughly describe how genetic engineering is used to make insulin.

Answer 15

1) The gene responsible for insulin production is identified and cut/removed out of the human DNA.
2) The gene will now have ‘sticky ends’ which are a set of unpaired based on either side or the gene.
3) Plasmids from bacteria are isolated and a section is cut out from the plasmid using Restriction Enzymes causing the plasmid to also have sticky ends.
4) The sticky end of both the plasmid and the insulin gene should have complementary based so they can be matched together.
5) The insulin gene is then ‘pasted’ into the plasmid by matching the ‘sticky ends’ in both, this is done using DNA ligase.
6) The Recombinant Plasmid is inserted into the bacteria and the bacteria are allowed to reproduce in a fermenter.
7) Each new bacterium formed will have the insulin gene and so will produce insulin.
8) The produced insulin is extracted from the bacteria in fermenters and is marketed.

Question 16

Explain Industrial Fermentation and how penicillin is produced.
What is the purpose of adding sugars and ammonium salts.

Answer 16

The fermentation vessel in a large tank filled with a medium containing the required nutrients. These include sugars and ammonium salts. The fungus penicillium is then added.

Sugar provides energy for respiration and ammonium salts are used by the fungus to make proteins and nucleic acids (DNA & RNA)

After a few days. The fungus starts to produce penicillin which accumulates in the fermenter.

Question 17

Explain Industrial Fermentation and how penicillin is produced.
What is the purpose of a stirrer in a fermenter?

Answer 17

A stirrer keeps the microorganisms suspended so they always have access to nutrients and oxygen. Stirring also helps maintain an even temperature throughout the fermenter.

Question 18

Explain Industrial Fermentation and how penicillin is produced.
Why is a steady air supply needed in a fermenter?

Answer 18

An air supply provides oxygen for aerobic respiration of the fungus to occur.

Question 19

Explain Industrial Fermentation and how penicillin is produced.
Why is a water cooled jacket needed in a fermenter?

Answer 19

A water cooled jacket removes the heat produced by fermentation to give a constant temperature of 24°C.

Question 20

Explain Industrial Fermentation and how penicillin is produced.
Why are probes required in a fermenter?

Answer 20

Probes monitor the temperature and make sure the pH is constant at 6.5 by adding any alkalis if necessary.

Question 21

What are the advantages of genetically modified crops? 3p

Answer 21

• Solving global hunger, genetic modification could feed more people as crops that are produced are able to tolerate extreme climate conditions and soils.
• Environmentally friendly, GM crops can be resistant to insects, weeds, diseases decreasing the need for pesticides.
• Consumer benefits, GM crops have already been produced with an improved flavour and better keeping qualities. They are easier to produce and require fewer additives.

Question 22

What are the disadvantages of Genetically Modified Crops? 3p

Answer 22

• Environmental safety, GM plants may become successful weeds. Pollen from GM crops that are resistant to weed killers may be transferred to other plants.
• Food safety, new gene combinations may have effects that are so far unknown. This may result in harmful substances being produced.
• Biodiversity, increasing the use of herbicides and plant breeding will reduce the number of plant varieties and wild relatives.