Meiosis and Fertilisation

• What process allows for the production of gametes in humans?

  Meiosis
• How many chromosomes are present in a normal human cell?


  46 chromosomes (23 pairs)
• How many single chromosomes are found in a human gamete?


  23 single chromosomes
• Where does meiosis occur in humans?


  In reproductive organs (testes in males and ovaries in females)
• What happens to chromosomes during the first stage of meiosis?


  All chromosomes are copied
• How many gametes are produced from one original cell during meiosis?


  Four gametes
• What is the genetic relationship between the gametes produced by meiosis?


  Each gamete is genetically different from each other
• What is the term used for the joining of male and female gametes?

  Fertilization
• What happens to the number of chromosomes after fertilization?


  The full number of chromosomes is restored
• What is the chromosome configuration of a fertilized egg?


  23 chromosome pairs
• What process occurs after fertilization to form an embryo?


  The fertilized egg divides by mitosis
• What is the term for the clump of identical cells formed after fertilization?

  Embryo
• What happens to the cells in an embryo as it develops?


  The cells differentiate into different cell types
• What are the key stages of meiosis that you need to know for the AQ8 specification?

  • Meiosis occurs in reproductive organs
  • Chromosomes are copied
  • The cell divides into two
  • Each of these cells divides again to form gametes
• What are the differences between gametes and normal human cells?


  • Gametes contain single chromosomes
  • Normal human cells contain paired chromosomes
  • Gametes have 23 single chromosomes
  • Normal human cells have 46 chromosomes (23 pairs)