Meiosis

• What process further increases genetic variation?

  Random fertilisation
• How many possible chromosome combinations are there in human gametes?

  2$^{23}$
• What is the significance of random fertilisation in genetic variation?

  It increases variation by random fusion of gametes
• What is the total number of combinations of chromosomes considering random fertilisation?

  (2$^{n}$)$^{2}$
• What does meiosis result in regarding genetic variation?

  Meiosis results in genetic variation
• What is the process of meiosis in a life cycle?

  • Involves a diploid (2n) parent cell
  • Divides to become haploid (n) cells
• What happens during crossing over in meiosis?

  Homologous pairs twist and exchange chromatids
• What causes tension on chromatids during crossing over?

  Twisting of homologous pairs at the equator
• What is the result of the broken chromatids recombining?

  New combinations of alleles
• How does meiosis differ from mitosis?

  Meiosis:

  • Two nuclear divisions
  • Produces haploid cells
  • Introduces genetic variation

  
  

  Mitosis:

  • One nuclear division
  • Produces diploid cells
  • Creates genetically identical cells
• What type of daughter cells does meiosis produce?

  Genetically different daughter cells
• How many haploid daughter cells are produced from meiosis?

  Four haploid daughter cells
• What are the two mechanisms that introduce variation in meiosis?

  1. Independent segregation of homologous chromosomes
  2. Crossing over between homologous chromosomes
• When do independent segregation and crossing over occur in meiosis?

  Both occur in meiosis 1
• What happens during independent segregation in meiosis 1?

  Homologous pairs line up randomly at the equator
• What is the outcome of the random arrangement of chromosomes during independent segregation?

  Creates a large number of possible chromosome combinations
• What does n represent of the calculations

  n is the number of homologous chromosomes paris