Unit 1: 6 - Variation, Reproduction and New Technology

Question 1

What are chromosomes?

Answer 1

Thread-like structures made of genes, found in the nucleus of a cell.

Question 2

What is different about gametes to normal cells?

Answer 2

Gametes contain only a single set of chromosomes (23 in humans), whereas normal cells contain 2 sets (46 in humans).

Question 3

What is asexual reproduction?

Answer 3

Reproduction that does not involve the fusion of gametes, where all the genetic information comes from one parent.

Question 4

What are clones?

Answer 4

Identical copies produced by asexual reproduction.

Question 5

What is a tissue culture?

Answer 5

Taking small groups of cells from part of a plant and growing them under special conditions.

Question 6

Why may cuttings be preferred to use over tissue culture?

Answer 6

They are easier to do and cheaper.

Question 7

Why may tissue culture be preferred to use over cuttings?

Answer 7

They can produce large numbers of rare and top-quality plants.

Question 8

Why are plants or animals genetically modified?

Answer 8

To produce useful substances, or carry better aesthetics or useful characteristics.

Question 9

What happens in adult cell cloning?

Answer 9

The nucleus of an adult cell (e.g. skin cell) replaces the nucleus of an egg cell.

Question 10

Describe the process that takes place in adult cell cloning.

Answer 10

Question 11

What is genetic engineering?

Answer 11

Changing the genetic make-up of an organism.

Question 12

How are genes cut out of a chromosone?

Answer 12

Using an enzyme.

Question 13

Genes may be placed in an organism of the same species to give it _____.

Answer 13

A desired characteristic.

Question 14

List at least 3 advantages and 3 disadvantages of cloning and genetic engineering.

Answer 14

Advantages

• Cloning cattle can produce herds of cattle with useful characteristics;
• Adult cell cloning may be used to make copies of the best animals, e.g. race horses;
• If a person has a faulty gene they may have a genetic disorder. If the correct gene can be transferred to the person they could be cured;
• Several medical drugs have been produced by genetic engineering, such as insulin and antibodies;
• GM crops include ones which are resistant to herbicides or to insects.

Disadvantages

• GM crops have a bigger yield, but farmers have to buy new GM seed every year because the crops are infertile;
• Some people are concerned about accidentally introducing genes into wild flower populations;
• Insects which are not pests may be affected by GM crops;
• Many people worry about the effect of eating GM crops on human health;
• Many people argue about whether or not cloning or genetic engineering are ethical. What will be the long-term effects? Will we create new organisms that we know nothing about? Are these processes ethically correct?