chapter 21

Question 1

Why are bacteria useful in biotechnology and genetic modification

Answer 1

1. capable of producing complex molecules like enzyme and hormones
2. they reproduce rapidly
3. NO ethical concerns over their manipulation and growth
   4.presence of plasmids
4. shares genetic code with all other organism
5. form complex molecules

Question 2

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

Answer 2

When yeast respires anaerobically, it produces ethanol and carbon dioxide

Question 3

Describe the use of pectinase in fruit juice production

Answer 3

pectinase breaks down chemical called pectin inside plant cell wall.
Once pectin is broken down, sugar is produced and more juice can be squeezed out of the fruit.

Adding pectinase also produces clearer juice as large polysaccharides like pectin can make juice seem cloudy

It also produces sweeter juice.

Question 4

Investigate and describe the use of biological washing powders that contain enzymes

Answer 4

The biological washing powders contain enzymes like amylase, protease and lipase

Advantages:
- quickly break down large insoluble molecules into small soluble ones that will dissolve in washing powder
- effective at low temperatures meaning less energy and money used

the powder should not be used in boiling water as it will denature the enzymes and powder will be ineffective

Explain why powder should bot be used to wash silk clothes
Powder contains protease which will cause silk to dissolve

Question 5

Explain how lactose-free milk is produced

Answer 5

use of enzyme lactase breaks down lactose into glucose and galactose

Question 6

Describe and explain the conditions that need to be
controlled in a fermenter

Answer 6

Sterile air ( Air provides oxygen for aerobic respiration . sterile to prevent entry of microorganism and pathogen )

Source of nitrogen ( to make protein, for growth and repair )

Carbohydrates ( source of energy )

Cooling water jacket
- maintain constant temperature
- prevent overheating of mixture ( respiration produces heat energy )
- prevent denaturation of enzyme

Temperature probe ( monitor the temperature )

pH probe ( monitor the pH, keep enzyme optimum, maximising the growth of microorganism )

Paddles / stirrer ( stir the mixture to allow microorganism to have better access to oxygen and nutrients , allows even distribution of heat / nutrients )

Question 7

Describe genetic modification

Answer 7

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

Question 8

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

Answer 8

1. restriction enzyme are used to cut required gene producing sticky ends
2. A bacterial plasmid is cut by the same restriction enzyme, producing complementary sticky ends
3. Plasmid and isolated gene joined together by DNA ligase to form recombinant DNA
4. The genetically engineered plasmid is inserted into the bacteria
5. Genetically engineered bacteria can be placed in a fermenter to reproduce rapidly and make large quantities of human protein

Question 9

State some examples of genetic modification

Answer 9

1. Gene for human insulin ( produces human insulin which can be collected and purified for medical use of diabetics )
2. Crop plants ( contains a gene that produces toxin that kills insects , making them resistant to insect pests )
3. Herbicide resistant crop plants ( herbicide only will kill weeds not the crop plant )
4. Crops have been genetically modified to produce additional vitamins (rice grains containing vitamin A )

Question 10

Discuss the advantages and disadvantages of genetically modifying crops

Answer 10

A:
Increase yield and quality of plants
Resistant to pests , herbicide, drought
More nutrients in the plant
Reduces usage of pesticide, less pollution to environment

D:
unknown health risk to consumers
GMO seeds are expensive
Herbicide resistance gene might be transferred to wild plants