cell division

• how many GENES do CHROMOSOMES carry?

  hundreds to thousands
• what are chromosomes found as?

  pairs
• THE CELL CYCLE

  1. the cell grows and increases the number of sub cellular structures then DNA is copied and new chromosomes are made
  2. mitosis
  3. cytoplasm and cell membrane split to form two IDENTICAL DAUGHTER CELLS
• what happens during mitosis?

  1. one set of chromosomes is pulled to each end of the cell
  2. the nucleus divides
  3. the cytoplasm and cell membrane get ready to split into two
• why is cell division important?

  • growth
  • repair
  • asexual reproduction
• what is a stem cell?

  • undifferentiated cell
  • that can split into different types of cells
• Embryonic stem cells


  • found in embryo
  • can make all types of cells
• Adult stem cells

  • found in bone marrow
  • can only make certain types of cells
  • capacity to divide is limited
• Why are stem cells important?

  they may be useful to treat conditions where cells are damaged or dont work properly. Eg. diabetes, paralysis
• what is therapeutic cloning?

  creating genetically identical stem cells using a patients embryo.
• how will stem cells from the cloned embryo be useful in treating the patient?

  they won’t be rejected by the patients body.
• concerns linked to using stem cells from cloned embryos

  • risks such as the transfer of a viral infection
  • ethical or religious objections
• where are stem cells found in plants?

  meristems
• what do meristems allow?

  they allow plants to make new cells for growth
• what can plant stem cells be used for?

  to produce clones of plants quickly
• why might producing clones for plants be useful?

  • a rare species can be clones for protection against extinction
  • lots of plants with special features such as disease resistance can be made