Cell Division and Stem Cells

• What are chromosomes?

  Long DNA molecules containing genes
• How many chromosomes do human body cells have?

  46 chromosomes arranged in 23 pairs
• What is a gene?

  A section of DNA that codes for protein
• What is mitosis used for?

  Growth, repair, and asexual reproduction
• What does mitosis produce?

  Two genetically identical daughter cells
• What is meiosis used for?

  Formation of gametes for sexual reproduction
• What does meiosis produce?

  Four genetically different daughter cells
• How many divisions occur in mitosis?

  One cell division
• How many divisions occur in meiosis?

  Two cell divisions
• What is the chromosome number in cells produced by mitosis?

  Full set (diploid)
• What is the chromosome number in cells produced by meiosis?

  Half set (haploid)
• What can happen if mitosis is uncontrolled?

  It can lead to cancer
• What are stem cells?

  Undifferentiated cells that can differentiate
• Why can't most mature cells differentiate?

  They have become specialised and lost ability
• Where are stem cells found?

  In both plants and animals
• What can embryonic stem cells become?

  Any type of cell (they are pluripotent)
• What can adult stem cells become?

  A limited range of specialised cells
• How can stem cells be used medically?

  To replace damaged tissues, e.g., in diabetes
• What is an ethical issue surrounding stem cells?

  The use of embryonic stem cells raises concerns
• Pluripotent

  Capable of developing into any type of cell or tissue
• Why is the number of chromosomes halved in gametes?

  Halving the number of chromosomes in the gametes ensures that when two gametes fuse during fertilisation, the resulting zygote has the correct diploid number of chromosomes.
• What are some examples of how stem cells are used in medicine?

  • Type 1 diabetes
  • Brain/spinal cord injuries
  • Organ repair or growth
  • Alzheimers/Parkinsons diesase
  • Sickle Cell diseases