4.6.1.1 Sexual and Asexual Reproduction

Question 1

What is the difference between mitosis and meiosis?

Answer 1

• meiosis leads to the formation of 4 non-identical haploid cells from one cell
• mitosis leads to the formation of 2 identical cells

Question 2

What does sexual reproduction involve?

Answer 2

• sexual reproduction involves the joining/fusion of male and female gametes
• as gametes are made by a process of meiosis each cell is genetically different to the other daughter cells
• during fertilisation (either external or internal) gametes fuse and produce an organism which has a full set of chromosomes
• the cell than divides by mitosis many times
• some of the embryonic stem cells start to differentiate/specialise and produce tissues that have a particular structure which enables them to carry out a specific function

Question 3

How does sexual reproduction take place in animals?

Answer 3

• fusion of animal gametes which are ova (ovum plural) and sperm
• produced in the ovaries or testes

Question 4

How does sexual reproduction take place in flowering plants?

Answer 4

• fusion of plant gametes which are egg cells/ovules and pollen
• produced in the ovaries or anthers

Question 5

Sexual reproduction:

Answer 5

• the formation of gametes involves meiosis as they are non-identical
• a normal cell has 46 chromosomes - there are 2 sets of chromosomes (23 pairs), in each pair one chromosome is from the father and the second set is from the mother
• each gamete has 23 chromosomes and they fuse in fertilisation
• in sexual production there genetic material from each gamete (parent) mix producing variation

Question 6

Asexual reproduction:

Answer 6

• asexual reproduction involves only one parent and no fusion of gametes
• there is no mixing of genetic information
• asexual reproduction takes placing using the process of mitosis where 2 identical cells are formed from 1 cell
• this leads to genetically identical offspring (clones) - which are genetically identical to each other and the parents