cell division

• cell cycle

  1. copy: 2 copies of chromosomes & internal cell structures
  2. mitosis: copies of chromosomes move and form 2 nuclei
  3. split: cytoplasm and cell membranes split to make 2 identical cells.
• mitotic cell division


  makes 2 identical copies of cells- used in growth and repair
• asexual reproduction


  form of reproduction using mitotic cell division to make clone cells
• chromosome

  1. contains large no. of genes- made of dna molecules
  2. human body cells contain 23 pairs of chromosomes
• genes


  instructions for a characteristics
• dna


  molecules that make genes
• cell differentiation

  1. stem cells can form diff types of specialised cells.
  2. most animal stem cells differentiate early
  3. many plant stem cells differentiate at any time
• clone


  genetically identical copy of a cell or organism
• stem cells


  not differentiated- can become any type of cell that is needed
• human stem cells

  1. embryos can become most types of human cell
  2. adult bone marrow can form many cells like rbc.
• human stem cells


  may be able to help conditions like diabetes and paralysis.
• issues with use of human stem cells

  • potential spread of virus or immune response
  • some people have ethical or religious objections
• meristem cells 


  plant stem cells- can become any type of plant cell at any time
• maristem cells


  used to clone:

  • rare plants from extinction
  • crops with desirable features
• ethical objections

  related to what a person thinks is morally good or ok