Sexual Reproduction (WJEC GCSE Biology)

Sexual Reproduction

Sexual reproduction

• Sexual reproduction is a process involving the fusion of the nuclei of two gametes (sex cells) to form a zygote (fertilised egg cell) and the production of offspring that are genetically different from each other and from the parents

  • The gametes of animals are the sperm cells and egg cells

  • The gametes of flowering plants are the pollen cells and egg cells

• Gametes contain one set of chromosomes from one parent (instead of two)

  • Gametes are formed through the process of meiosis

• Fertilisation is defined as the fusion of gamete nuclei, and as each gamete comes from a different parent, there is a new combination of chromosomes in the zygote

  • This produces variation in the offspring

Asexual reproduction

• Asexual reproduction does not involve gametes or fertilisation

• Only one parent is required so there is no fusion of gametes and no mixing of genetic information

• As a result, the offspring are genetically identical to the parent and to each other (clones)

• Asexual reproduction is defined as a process resulting in genetically identical offspring from one parent

• Only mitosis is involved in asexual reproduction