Meiosis stages

• What type of cell do we start with in meiosis?

  Diploid cell
• How many haploid gametes are produced from meiosis?


  Four haploid gametes
• What happens to chromosomes during meiosis?

  They are separated into individual chromosomes
• How many rounds of nuclear division occur in meiosis?

  Two rounds of nuclear division
• What is separated during meiosis 1?

  Homologous chromosomes
• What is separated during meiosis 2?

  Sister chromatids
• What is the first stage of meiosis 1?

  Prophase 1
• What occurs during interphase before meiosis starts?

  The cell copies chromosomes and organelles
• What happens to chromosomes during prophase 1?

  Chromosomes condense and become visible
• What forms when homologous chromosomes link together?
• What is crossing over?

  Exchanging alleles between homologous chromosomes
• What happens during anaphase 1?

  Homologous chromosomes move towards opposite poles
• What occurs in telophase 1?

  Nuclear membranes reform and chromosomes uncoil
• What type of cells are produced after meiosis 1?

  Haploid cells
• What happens during anaphase 2?

  Centromeres divide and chromatids are pulled apart
• What is the result of telophase 2?

  Four haploid cells are produced
• Why is meiosis called reduction division?

  Because the chromosome number halves
• What is independent assortment?

  Random distribution of maternal and paternal chromosomes
• What are the two main sources of genetic variation in meiosis?

  Crossing over and independent assortment
• How many chromosome pairs do human cells have?

  23 chromosome pairs
• How many genetically different gametes can independent assortment produce?

  $2^n$ where $n$ is pairs
• What is the number of genetically different gametes from humans?

  Over 8 million
• What does random fusion of gametes introduce?

  Extra genetic variation in offspring
• What are the stages of meiosis?

  1. Meiosis 1:

  • Prophase 1
  • Metaphase 1
  • Anaphase 1
  • Telophase 1

  1. Meiosis 2:

  • Prophase 2
  • Metaphase 2
  • Anaphase 2
  • Telophase 2
• How does meiosis contribute to genetic variation?

  • Crossing over during prophase 1
  • Independent assortment during metaphase 1
  • Random fusion of gametes during fertilization
• What is the significance of cytokinesis in meiosis?


  • Divides the cytoplasm
  • Produces haploid cells
  • Occurs after telophase 1 and telophase 2