Chromosomes and mitosis

• Chromosomes are coiled up lengths of DNA molecules
• 23 pairs of chromosomes
• Cell cycle

  1. body cells in multicellular organisms divide to produce new cells
  2. mitosis- cell divides
  3. multicellular organisms use mitosis to grow/replace damaged cells
  4. end to cycle 2 new cells identical to the OG cell, with same number of chromosomes
• Growth and DNA replication

  1. in the cell that’s not dividing the DNA I spread out in long strings
  2. Before divide, the cell grows and increases the amount of sub cellular structures (mitochondria, ribosomes)
  3. duplicates it’s DNA- forms X shaped chromosomes, each arm of the chromosome is an exact duplicate
• Mitosis

  once contents and DNA has been copied ready for mitosis

  1. the chromosomes line up at the centre of the cell and cell divers pull them apart- 2 arms of each chromosome go to opposite ends of the cell
  2. membranes from around each of the sets of chromosome- these become the nuclei of the two new cells- nucleus has divided
  3. the cytoplasm and cell mem divide- 2 new daughter cells contain same DNA are identical. their DNA is also the same to parent cell