Asexual and Sexual Reproduction

Question 1

What is meiosis?

Answer 1

the formation of four non-identical cells from one cell

Question 2

What is mitosis?

Answer 2

the formation of two identical daughter cells from one cell

Question 3

What does sexual reproduction involve?

Answer 3

the joining of male and female gametes, each containing genetic information from the mother or father
- sperm and egg cells in animals
- pollen and egg cells in plants

Question 4

Gametes:

Answer 4

• formed by meiosis as they are non identical
• a normal cell has 46 chromosomes: 23 from from mother and other from father
• each gamete has 23 chromosomes and they fuse in fertilisation
• the genetic information from each parent is mixed, producing variation in the offspring

Question 5

What does asexual reproduction involve?

Answer 5

• one parent with no gametes joining/ no mixing of genetic information
• happens in process mitosis
• leads to cloning (which are genetically identical to each other and the parent)
• used by bacteria, some plants, some animals

Question 6

Advantages of sexual reproduction:

Answer 6

1) Produced variation in the offspring
- the organism could have characteristics that allow them to survive decreasing the chance of extinction

2) Selective breeding
- can breed organisms with desirable characteristics, speeding up natural selection

Question 7

Advantages of asexual reproduction:

Answer 7

• only one parent is needed
• uses less energy and is faster as the organism does not need to find a mate
• lots of identical offspring can be produced

Question 8

Examples of organisms which can use both methods to reproduce:

Answer 8

1) malarial parasites
- reproduce sexually in mosquito
- reproduce asexually in the human host (in liver and blood cells)

2) plants
- reproduce sexually using pollen, which much reach egg cells in female plant, forming seeds
- reproduce asexually by producing bulbs, which can grow from the main one