chromosomes and mitosis

• nucleus contains genetic material in the form of chromosomes (coiled up lenths of dna molecules), each chrorosomes contains genes that control different characteristics (e.g hair colour), body cells have two copies of each chromosome (one each from mum and dad), there are 23 pairs in a human cell.
• the cell cycle (part 1 growth and dna replication):

  1. while cells are not dividing dna is streched out in long strings
  2. before it divides it grows more subcellular structures (e.g mitrocondria)
  3. it duplicates its dna, the copied dna froms x-shaped chromosomes (each arm of the chromosomes are duplicates of the others)
• the cell cycle (part 2 mitosis):

  1. chromosomes are pulled apart by cell fibers
  2. membrains form around each set of chromosomes and become two new nuclei
  3. lastly, the cytoplasm and cell membrane divide
  4. the two daugher cells are identical to the parent cell