Meiosis

• What is diploid ?

  Two sets of chromosomes
• What is haploid?

  One set of chromosomes
• What is haploid represented by?

  n
• What is diploid represented by?

  2n
• Are gametes diploid or halploid?

  Haploid
• Why are gametes haploids?

  They come together through fertilisation to make a diploid
• How many chromosome are there in a haploid?

  23
• What is the main advantage of meiosis?

  Gives genetic diversity
• How can you tell where meiosis is occurring on a life cycle?

  Where 2n turns to n
• Describe the process of meiosis.

  DNA unravels and replicates to form copies of each chromosome called chromatids. DNA condenses to form double armed chromosome with sister chromatids joint by centromere. First division occurs and chromosomes move to opposite poles. This halves the chromosome number. Second division occurs and chromatids move to opposite poles as the centromere is divided. Produces four genetically different haploid cells.
• Explain crossing over of chromatids.

  Homologous chromosomes align next to eachother and twist around eachother to swap bits of chromatids. Same genes but different alleles. Creates genetic variation.
• Explain independent segregation of chromosomes.

  Random which chromosome (mother or father) ends up in daughter cell. There is many different combinations. This increases genetic diversity.
• How do u calculate number of chromosome combinations?

  2n (n- number of homologous pairs)
• How is meiosis different to mitosis?

  It produces half number of chromosomes as parent cell. Daughter cells are genetically different in meiosis. Produces 4 daughter cells in meiosis.