Cell division and stem cells

• Why do cells divide by mitosis?

  For growth and repair
• Why do cells divide of meiosis?

  To produce gametes (sex cells) for reproduction
• When do stem cells differentiate into specialised cells?

  During development of organisms
• What does mitosis do?

  Ensures that when a cell divides, each new cell has the same genetic information
• How many chromosomes does each body cell have?

  46
• What are chromosomes arranged into?

  23 pairs
• What is this process called?

  Mitosis

  
• What is this process called?

  Meiosis

  
• When do cells divide

  1. When an organism grows
  2. When worn-out cells need replacing
  3. When tissue need to be repaired
• What is produced in mitosis?

  Two daughter cells that are genetically identical
• Why does cancer spread?

  Cancerous cells begin to grow and divide uncontrollably due to mitosis
• What can cause cancer?

  • Carcinogens
  • Viruses linked to cancer
  • Alcohol
  • UV radiation
  • Poor diet
• What is a gamete?

  A sex cell produced in the testes/ovaries
• How many chromosomes do gametes contain?

  23
• What happens when a male and female gamete fuse?

  They become a zygote (fertilised egg cell)
• What is the fusion of gametes called?

  Fertilisation
• How are gametes formed?

  By meiosis
• What kind of reproduction is meiosis?

  Sexual
• What kind of reproduction is mitosis?

  Asexual
• What are the gametes in plants?

  The pollen and eggs
• What happens in meiosis?

  1. Copies of genetics are made
  2. Cells divide twice to produce 4 daughter cells known as haploid
• What are the gametes in meiosis?

  Genetically different
• What is a haploid cell?

  A cell with only one complete set of chromosomes
• What is diploid?

  A cell with two complete sets of chromosomes
• What are stem cells?

  Cells in the early stages of the development of an embryo
• What have stem cells not done?

  They haven’t undergone differentiation
• What is differentiation?

  When an unspecialised cell becomes more specialised
• What is a specialised cell?

  A cell that have become differentiated to carry out a particular function
• Where can adult stem cells be found?

  • Brain
  • Eyes
  • Blood
  • Heart
  • Liver
  • Bone Marrow
  • Skin
  • Muscle
• What can bone marrow cells do?

  They can differentiate into blood cells and the cells of the immune system
• When can stem cells be used?

  • in type 1 diabetes
  • multiple sclerosis
  • spinal cord and brain injury
• Which stem cells can be used for transplantation?

  Embryonic stem cells and adult stem cells.
• What can embryonic stem cells do?

  Can differentiate into a wide range of cell types
• Whats a weakness of embryonic stem cells?

  Difficult to obtain
• What can adult stem cells do?

  Differentiate into a narrower range of cell types
• When are bone marrow transplants carried out?

  • In blood cell cancer
  • When blood cells have been destroyed
• What are the advantages of stem cells in medicine?

  • No rejection
  • No donor needed
  • No tissue typing needed
• What are the clinical issues with using stem cells?

  • no guarantee of success
  • difficulty in finding donors
  • difficult to obtain
  • could transfer viruses
  • could cause cancer
• What are the ethical issues with using stem cells?

  • embryos can be destroyed
  • prevents potential life
• What are the social issues with using stem cells?

  • whether benefits our way risks
  • patients could be exploited due to expensive treatment