Mitosis and the cell cycle

• Cells divide in a series of stages called the cell cycle.
• During the cell cycle the genetic material is doubled and then divided into two identical cells. Before a cell can divide it needs to grow and increase the number of subcellular structures such as ribosomes and mitochondria. The DNA replicates to form two copies of each chromosome. In mitosis one set of chromosomes is pulled to each end of the cell and the nucleus divides. Finally the cytoplasm and cell membranes divide to form two identical cells.
• Cell division by mitosis is important in the growth and development of multicellular organisms.
• Cells go through a series of changes involving growth and division, called the cell cycle
• One of the stages of mitosis, when a cell divides into two identical cells.

  Before cells can divide, it needs to grow and increase the number of subcellular structures, such as ribosomes and mitochondria.
• The DNA then replicates to form two copies of each chromosome.
• Mitosis:

  1. Parent cell with two pairs of chromosome
  2. Each chromosome replicates itself
  3. Chromosomes line up along the centre of the cell, divide and the copies move to opposite poles
  4. Each 'daughter' cell has the same number of chromosomes, and contains the same genes as the parent cell
• Cell division by mitosis is important because it makes new cells for:

  • growth and development of multicellular organisms
  • repairing damaged tissues
  • asexual reproduction
• Water may move across cell membranes by osmosis
• Osmosis is that diffusion of water from a dilute solution to a concentrated solution through a partially permeable membrane
• A dilute solution contains lots of water. A concentrated solution contains less water.