Reproduction

Question 1

What is sexual reproduction?

Answer 1

fusion of a male and female gametes

mixture of genetic information from parents leads to variation in offspring

Question 2

What is asexual reproduction?

Answer 2

only one individual needed as parent

no mixing of genetic information so no genetic variation

genetically identical individuals are known as clones

Question 3

Cuttings

Answer 3

branch of parent plant is cut off

stem is planted in soil

plant hormones used to encourage new roots to develop

cutting covered in a clear plastic bag to maintain moisture and warmth

easiest method

Question 4

Tissue culture

Answer 4

small groups of cells used

placed in sterile agar jelly with plant hormones and nutrients

more difficult and expensive

Question 5

Embryo transplant

Answer 5

developing embryo removed from pregnant animal before cells become specialised

cells are separated from one another

grown in laboratory then transplanted into mother

offspring are identical

Question 6

Adult cell cloning

Answer 6

1) nucleus removed from unfertilized egg and discarded
2) nucleus removed from adult body cell and injected into egg cell
3) electric shock used to make egg divide and form embryo
4) while still a ball of cells, the embryo is inserted into a womb
5) embryo continues to grow and develop
- contains same genetic information as adult cell

Question 7

How is genetic engineering done?

Answer 7

• genes from the chromosomes are cut out using enzymes and transferred to cells of another
• genes transferred at an early stage of an organisms development so they develop with the desired characteristics

Question 8

Effects of GM crops

Answer 8

• examples of GM crops - resistant to insect attack or to herbicides
• increase crop yield

concerns:

• effect on wild flowers and insects
• uncertainty on effects on human health