Producing Cells

Producing Cells

1. stem cells

   • they are unspecialised cells
   • they can turn into any other type of cell
   • they are used for growth and repair
   • can be found in embryos and an adults bone marrow
     • the bone marrow stem cells can only turn into certain types of cells

2. cell division

   • this is called mitosis
   • how?
     • step 1: the chromosomes are long and uncoiled
       • step 2: the chromosomes shorten and thicken and create chromatids
         • step 3: chromatids line up across the equator of the cell and spindle fibres connect them to the poles of the cell
           • step 4: chromatids are pulled to the poles the cell by the spindle fibres
             • step 5: cell membrane starts to split into two different cells
               • step 6: the parent cell creates two daughter cells with a full chromosome complement

3. types of cells

   • diploid cells
     • these cells have 2 sets of chromosomes
     • skin cells, muscle cells, tissue cells and nerve cells and examples of diploid cells
   • haploid cells
     • these cells have 1 set of chromosomes
     • these are 'sex cells' or gametes
     • sperm, eggs, pollen and ovules

4. chromosomes

   • a full set is called the chromosome complement
     • the chromosome complement of humans is 46 (23 pairs)
     • if a cell does not have the correct number of chromosomes it will not function properly