Meiosis

• What is the end result of meiosis?

  Meiosis produces gametes that have half the genetic material of the parent cell
• How is cell division similar for non-sex versus sex cells?

  Both processes involve the duplication of genetic material
• How is cell division different for non-sex versus sex cells?

  Sex cells undergo meiosis, while non-sex cells undergo mitosis
• Why are gametes genetically unique from one another?

  Due to crossing over and independent assortment during meiosis
• What is crossing over in meiosis?

  It is the exchange of genetic material between homologous chromosomes
• What is independent assortment in meiosis?

  It is the random distribution of maternal and paternal chromosomes into gametes
• What is nondisjunction and what effect can it have?

  Nondisjunction is the failure of chromosome pairs to separate, leading to an abnormal number of chromosomes
• How many chromosomes are in a human somatic cell?

  46 total chromosomes
• How many chromosomes are in a human reproductive (sex) cell?

  23 total chromosomes
• What is the karyotype of a human somatic cell?

  It has two copies of each chromosome, making it diploid (2n)
• What is the goal of meiosis?

  To create gametes that have half the amount of genetic material as the parent cell
• What happens during Prophase I of meiosis?

  Homologous pairs of sister chromatids come together
• What occurs during Metaphase I of meiosis?

  Independent assortment of chromosomes takes place
• How many chromosomes will there be within each gamete if a cell contains 6 total chromosomes?

  3 chromosomes in each gamete
• What is the result of nondisjunction in meiosis?

  It can lead to conditions such as Trisomy 21
• How many total chromosomes does a person with Trisomy 21 have?

  47 total chromosomes
• What is Turner Syndrome?

  It is a condition caused by nondisjunction resulting in a female with one X chromosome (XO)
• What is Klinefelter Syndrome?

  It is a condition caused by nondisjunction resulting in a male with an extra X chromosome (XXY)
• What is the condition of an individual with XYY chromosomes?

  It is referred to as "supermale" due to nondisjunction
• What are the key differences between mitosis and meiosis?

  • Mitosis:
  • Purpose: Growth/repair
  • Number of divisions: 1
  • Parent cell: 2n (diploid)
  • Daughter cells: 2 (identical to parent)
  • Occurs in somatic cells

  
  

  • Meiosis:
  • Purpose: Reproduction
  • Number of divisions: 2
  • Parent cell: 2n (diploid)
  • Daughter cells: 4 (unique)
  • Occurs in gonads
• What are the characteristics of daughter cells produced by mitosis and meiosis?

  • Mitosis:
  • 2 daughter cells
  • Genetically identical to parent
  • Chromosome number: 46

  
  

  • Meiosis:
  • 4 daughter cells
  • Genetically unique
  • Chromosome number: 23
• Does crossing over occur in mitosis?

  No, crossing over does not occur in mitosis
• What is the significance of crossing over in meiosis?

  It increases genetic diversity among gametes
• How does nondisjunction affect chromosome number in gametes?

  Nondisjunction can result in gametes with an abnormal number of chromosomes
• What is the chromosome number of a human gamete?

  23 chromosomes
• What is the role of the ovaries and testes in meiosis?

  They are the locations where sex cells are produced
• How does the process of meiosis contribute to evolution?

  Meiosis introduces genetic variation, which is essential for natural selection