Specialised cells

• what is differentiation?

  • When cell gains new sub cellular structures to be suited to its role
• Name 3 specialised human cells

  • Sperm cell
  • Muscle cell
  • Nerve cell
• Name 3 specialised plant cells

  • Phloem
  • Xylem
  • Root hair cell
• What is the function of the sperm cell

  • Carries male DNA to ovum for successful reproduction
• What is the function of a nerve cell?

  • Transmits electrical signals quickly from one part of the body to another
• What is the function of a muscle cell?

  • Contracts quickly to cause movement
• How is a sperm cell specialised?

  • Streamlined head and long tail to aid swimming
  • Lots of mitochondria which supplies energy for movement through respiration
  • Acrosome has digestive enzymes which break down outer layer of egg
• How is a nerve cell specialised?

  • Long axon to carry impulses over long distances
  • Lots of dendrites to form branched connections with other cells
  • Nerve endings have lots of mitochondria to supply energy to make neurotransmitters
• How is a muscle cell specialised?

  • Special proteins myosin and actin slide over each other causing the muscle to contract
  • Lots of mitochondria to provide energy from respiration for contraction
  • Store glycogen which is can be used in respiration by mitochondria
• What is the function of a root hair cell?

  • Take up water by osmosis and mineral ions by active transport
• What is the function of a xylem cell?

  • Transport water and mineral ions up plant from roots to shoots
• What is the function of a phloem cell?

  • Carry products of photosynthesis to all parts of the plant
• How is a root hair cell specialised?

  • Lots of mitochondria to provide energy for active transport
  • Large surface area due to root hairs so more water can move in
  • Large permanent vacuole affects speed of movement of water from soil to plant
• How are xylem cells specialised?

  • Made of lignin which strengthens walls to withstand high pressure
  • Made of dead cells which means they have no organelles and this maximises space for water transportation
  • Tubes are hollow which allow water and minerals to flow through without obstruction
• How are phloem cells specialised?

  • Has sieve plates that allow sugars and nutrients to flow between cells
  • Companion cells have mitochondria which provides the cell with energy
  • Can transport substances in both direction depending on plants needs