Meiosis and Genetic Variation

• What is the main exception to the rule that body cells contain the same genetic information?

  Gametes
• What type of cells have the diploid number of chromosomes?

  Diploid body cells
• How many chromosomes do humans have in total?

  46 chromosomes
• What are homologous pairs of chromosomes?

  Pairs of matching chromosomes with alleles
• What is the haploid number of chromosomes for humans?

  23 chromosomes
• What happens during fertilization?

  A haploid sperm fuses with a haploid egg
• How does random fertilization contribute to genetic diversity?

  It produces zygotes with different chromosome combinations
• What is meiosis?

  A type of cell division for gametes
• What is the starting chromosome number for cells that undergo meiosis?

  Diploid
• What is the result of meiosis in terms of chromosome number?

  Chromosome number halves
• What do meiosis produce in humans and other mammals?

  Gametes
• What happens to DNA before meiosis starts?

  DNA unravels and replicates
• What are sister chromatids?

  Two copies of each chromosome
• What occurs during Meiosis I?

  Homologous chromosomes arrange into pairs
• What happens to homologous pairs during Meiosis I?

  They are separated, halving chromosome number
• What occurs during Meiosis II?

  Sister chromatids are separated
• How many haploid cells are produced from meiosis?

  Four haploid cells
• What are the two main events during meiosis that lead to genetic variation?

  1. Crossing over of chromatids
  2. Independent segregation of chromosomes
• What is crossing over during meiosis?

  Chromatids swap segments, creating new alleles
• What is independent segregation of chromosomes?

  Random separation of maternal and paternal chromosomes
• How does independent segregation contribute to genetic variation?

  It creates different combinations of chromosomes
• What is the significance of genetic variation in offspring?

  • Increases adaptability to environments
  • Enhances survival of species
  • Promotes evolution
• Why is meiosis necessary for sexual reproduction?

  It ensures gametes have half the chromosome number
• In the life cycle of the malaria parasite, where does meiosis occur?

  In the mosquito's gut
• What is the only diploid stage in the malaria parasite's life cycle?

  The zygote
• How does the chromosome number change during the zygote's division?

  It halves to form haploid sporozoites
• What is the purpose of meiosis in organisms?

  It produces gametes with half the chromosomes
• What happens to the chromosome number during the divisions of haploid cells in the malaria life cycle?

  The chromosome number stays the same
• How many daughter cells does meiosis produce?

  Four daughter cells
• What is a key difference between the outcomes of mitosis and meiosis?

  Mitosis produces identical cells, meiosis does not
• How many divisions occur in meiosis compared to mitosis?

  Meiosis has two divisions, mitosis has one
• What processes are absent in mitosis that occur in meiosis?

  Pairing and separating of homologous chromosomes
• What is the result of crossing over in meiosis?

  Genetically different daughter cells
• What is independent segregation of chromosomes?

  Random distribution of maternal and paternal chromosomes
• What are the outcomes of mitosis and meiosis?

  Mitosis:

  • Produces two identical daughter cells
  • Same chromosome number as parent cell

  
  

  Meiosis:

  • Produces four genetically different daughter cells
  • Half the chromosome number of parent cell
• What are the key differences between mitosis and meiosis?

  • Mitosis: one division, identical cells
  • Meiosis: two divisions, genetically diverse cells
  • Mitosis: no crossing over, meiosis: crossing over occurs