Cell specialisation

• Differentiation

  The process involves the cell gaining new sub-cellular structures in order for it to be suited to its role
• Types of cell differentiation

  • Cells can either differentiate once early on or have the ability to differentiate their whole life
• Types of cells in animals

  • Sperm cells
  • Nerve cells
  • Muscle cells
• Sperm cells

  • Specialised to carry the male's DNA to the egg cell for successful reproduction
  • Streamlined head and long tail to aid swimming
  • Many mitochondria which supply the energy to allow the cell to move
• Nerve cells

  • Specialised to transmit electrical signals quickly from one place in the body to another
  • The axon is long, enabling the impulses to be carried along long distances
  • Having lots of extensions from the cell body means branched connections can form with other nerve cells
  • The nerve endings have many mitochondria which supply the energy to make special transmitter chemicals called neurotransmitters. These allow the impulse to be passed from one cell to another
• Muscle cells

  • Specialised to contract quickly to move bones or simply to squeeze, therefore causing movement
  • Special proteins slide over each other, causing the muscle to contract
• Types of cells in plants

  • Root hair cells
  • Xylem cells
  • Phloem cells
• Root hair cells

  • Specialised to take up water by osmosis and mineral ions by active transport from the soil as they are found in the tips of roots
  • Have a large surface area due to root hairs, meaning more water can move in
  • The large permanent vacuole affects the speed of movement of water from the soil to the cell
  • Mitochondria to provide energy from respiration for the active transport of mineral ions into the root hair cell
• Xylem cells

  • Specialised to transport water and mineral ions up the plant from the roots to the shoots
  • Upon formation, a chemical called lignin is deposited which causes the cells to die. They become hollow and are joined end-to-end to form a continuous tube so water and mineral ions can move through
  • Lignin is deposited in spirals which helps the cells withstand the pressure from the movement of water
• Phloem cells

  • Specialised to carry the products of photosynthesis to all parts of the plants
  • Cell walls of each cell form structures called sieve plates when they break down, allowing the movement of substances from cell to cell