Cell Specialisation

• What is a specialised Cell?

  A specialized cell is a cell that has a specific structure and function to perform a particular task in the body.
• Nerve cells (neurones) have an elongated structure which allows them to coordinate information from the brain and spinal cord with the rest of the body.
• What is the function of a nerve cell?

  The function of a nerve cell, also known as a neuron, is to transmit electrical signals and communicate information throughout the body.
• Nerve cells have special features that aid their function:

  • Nerve cells are long, meaning that they can conduct nerve impulses between different areas of the body
  • Extensions of the cytoplasm known as dendrites allowing nerve cells to communicate with other nerve cells, muscles and glands
  • The axon is covered with a fatty sheath which speeds up nerve impulse transmission
• Muscle cells contain layers of fibres which allow them to contract.
• What is the function of a muscle cell?

  Contraction for movement.
• Muscle cells have special features that aid their function:

  • Muscle cells have many mitochondria to release energy for contraction
  • All muscle cells contain protein filaments that can slide over each other to allow muscle contraction
• Sperm cells are mobile - their tail helps propel them forward in search of an egg cell
• What is the function of a sperm cell?


  To transfer genetic material to an egg cell for fertilisation.
• Sperm cells have special features that aid their function:

  • The mid-piece is packed with mitochondria to release energy (via respiration) for the tail
  • The tail rotates, propelling the sperm cell forward and allowing it to move
  • The acrosome in the head contains digestive enzymes that can break down the outer layer of an egg cell so that the haploid nucleus can enter to fuse with the egg’s nucleus
  • The head contains a nucleus with half the normal number of chromosones, allowing the sperm cell to fuse with an egg cell to restore the normal chromosone number.
• The root hair cell is an extension of the cytoplasm, increasing the surface area of the cell in contact with the soil to maximise absorption of water and minerals.
• What is the function of a root hair cell?


  Absorption of water and mineral ions from soil.
• Root hair cells have special features that aid their function:

  • Root hairs increase surface area (SA) so the rate of water uptake by osmosis is greater
  • Thinner walls than other plant cells so that water can move through easily due to shorter diffusion distance
  • Mitochonria release energy for active transport of mineral ions
• Xylem cells lose their top and bottom walls to form a continuous tube through which water moves from the roots to the leaves.
• What is the function of a xylem cell?

  Transport of water and dissolved ions.
• Xylem cells have special features that aid their function:

  • No walls between cells to form continuous hollow tubes through which water is drawn upwards towards the leaves
  • Cells contain no organelles or cytoplasm, allowing free passage of water
  • Outer walls are thickened with a substance called lignin, strengthening the tubes and providing support for the plant
• Phloem cells are adapted for the transport of dissolved sugars and amino acids.
• What is the function of a phloem cell?

  Transportation of dissolved sugars and amino acids.
• Phloem cells have special features that aid their function:

  • Cells are joined end-to-end and contain holes in the end cell walls (sieve plates); this forms tubes which allow sugars and amino acids to flow easily
  • Cells have very few subcellular structures to aid the flow of materials