Paper 2 - Use of Biological Resources

Question 1

Why are fished farmed?

Answer 1

To provide a source of protein

Question 2

In a fish farm, how do you maintain water quality?

Answer 2

Filter water to remove waste and harmful bacteria to prevent disease

Question 3

In a fish farm, how do you control intraspecific predation?

Answer 3

Fish are separated by size and age to prevent competition

Question 4

In a fish farm, how do you control interspecific predation?

Answer 4

Fish of different species are separated by nets or tanks

Question 5

In a fish farm, how do you control disease?

Answer 5

Give antibiotics to increase chances of survival

Question 6

In a fish farm, how do you remove waste product?

Answer 6

Water is filtered to remove waste faeces

Question 7

In a fish farm, how do you control the quality and frequency of breeding?

Answer 7

Fish are fed frequently but in small amount to they do not overeat and to avoid food wastage

Question 8

In a fish farm, why do you do selective breeding?

Answer 8

To reproduce fish with desired characteristics

Question 9

Describe the process of micropropagation (tissue culture) in which explants are grown in vitro

Answer 9

• A plant with desirable characteristics is selected to be cloned. Small pieces (explants) are taken from the tips of stems and the side shoots of this plant
• The explants are sterilised to kill any microrganisms
• The explants are then grown in vitro - they are placed in a petri dish containing a nutrient medium. The medium has all the nutrients the explants need to grow. It also contains growth hormones
• Cells in the explains divide and grow into a small plant. If large quantities of plants are required, further explants can be taken from this smalls plants and so on until enough small plants are produced
• The small plants are taken out of the medium, planted in soil and put into glasshouses where they will develop into genetically identical copies of the original plant so will share the same characteristics

Question 10

Describe the stages in the production of cloned mammals involving the
introduction of a diploid nucleus from a mature cell into an enucleated egg
cell, illustrated by Dolly the sheep

Answer 10

• The nucleus of a sheep’s egg was removed, creating an enucleated cell (a cell without a nucleus)
• A diploid nucleus was inserted in its place. This was a nucleus from a mature udder cell of a different sheep
• The cell was stimulated by an electric shock so that it started dividing my mitosis as if it were a normal fertilised egg
• The dividing cell was implanted into the uterus of another sheep to develop until it was ready to be born
• The result was Dolly, a clone of the sheep that the udder cell came from

Question 11

How can cloned transgenic animals be used to produce human
proteins?

Answer 11

• Cows and sheep make protein naturally in their milk. By transferring human genes into the cells of these animals, researchers have managed to get them to produce useful human proteins in their milk
• E.g. they can produce human antibodies that can be used in therapy for illnesses like arthritis, some types of cancer and multiple sclerosis
• Transgenic chickens have also been engineered to produce human proteins in egg white
• These transgenic animals can then be cloned so that the useful genetic characteristic is passed on - this doesn’t always happen with breeding