chapter 21: biotechnology and genetic modification

Question 1

give 4 reasons why bacteria are useful in biotechnology and genetic modification

Answer 1

1. capable of producing complex molecules
2. reproduce quickly
3. few ethical considerations regarding their use
4. they possess plasmids

Question 2

describe the role of anaerobic respiration in yeast during the production of ethanol for biofuels

Answer 2

it breaks down glucose into ethanol which is used as biofuel

Question 3

describe the role of anaerobic respiration in yeast during bread-making

Answer 3

it breaks down glucose into carbon dioxide which is used to make the bread rise

Question 4

describe 2 uses of pectinase in fruit juice production

Answer 4

1. breaks down pectin in cell walls, making the cell walls break down more easily so more juice is released
2. produces a clearer juice as larger polysaccharides like pectin can make the juice seem cloudy

Question 5

describe 3 advantages of using biological washing powders containing enzymes

Answer 5

1. quickly breaks down large insoluble molecules into small soluble molecules
2. effective at lower temperatures so less energy and money is needed
3. cleans delicate fabrics that can’t be washed at high temperatures

Question 6

what is the use of lactase?

Answer 6

to produce lactose free milk

Question 7

describe how fermenters can be used for the large-scale production of useful products by bacteria and fungi

Answer 7

• fermenters grow cultures in large amounts
• used for many biotechnological processes like producing genetically modified bacteria and fungi including insulin, penicillin, mycoprotein

Question 8

describe and explain the conditions that need to be controlled in a fermenter, including: temperature, pH, oxygen, nutrient supply and waste products

Answer 8

1. temperature: monitored with probes and maintained with water jacket to ensure optimum enzyme activity and prevent denaturation
2. pH: monitored with probes and adjusted with acids and alkalis for optimum enzyme activity
3. oxygen: oxygen required for aerobic respiration
4. nutrient supply: needed for respiration to release energy for growth and reproduction of microorganisms
5. waste products: contents are filtered to remove waste created by the microorganisms

Question 9

define genetic modification

Answer 9

changing the genetic material of an organism by removing, changing or inserting genes

Question 10

list 4 examples of genetic modification

Answer 10

1. the insertion of human genes into bacteria to produce human proteins
2. the insertion of genes into crop plants to confer resistance to herbicides
3. the insertion of genes into crop plans to confer resistance to insect pests
4. the insertion of genes into crop plants to improve nutritional qualities

Question 11

outline the process of genetic modification using bacterial production of a human protein

Answer 11

1. isolation of DNA making up a human genes using restriction enzymes, forming sticky ends
2. cutting of bacterial plasmid using same restriction enzyme, forming complementary sticky ends
3. insertion of human DNA into bacterial plasmid DNA using DNA ligase to form a recombinant plasmid
4. insertion of recombinant plasmids into bacteria
5. multiplication of bacteria containing recombinant plasmids
6. expression in bacteria of the human gene to make the human protein

Question 12

discuss the advantages and disadvantages of genetically modifying crops, including soya, maize, and rice

Answer 12

advantages:
1. reduced use of chemicals
2. higher yield of crops produced
3. less time-consuming for farmers

disadvantages
1. increased costs of seeds
2. reduced biodiversity
3. risk of wild plants getting the altered genes
4. increased dependency of certain chemicals