Cell specialisation and differentiation

• How are the muscle cells specialised for contraction?


  • Proteins (mysoin & actin) slide over each other- causes the contraction
  • Many mitochondria- provides energy
  • Stores glycogen- used in respiration
• How are nerve cells specialised to transmit electrical signals?


  • Axon long- cover more distance
  • Branched ends (dendrites)- form connections to other nerve cells
  • Nerve endings have many mitochondria- supplies energy to make neurotransmitters
• How are sperm cells specialised for reproduction?


  • Long tail & streamlined head- to help swim to egg
  • Lots of mitochondria- provides energy
  • Enzymes in head- to digest through egg cell membrane
• How are root hair cells specialised for absorbing water and minerals?


  • Large surface area- increased rate of osmosis & active transport
  • Large permanent vacuole- more cell sap than water- increases rate of osmosis
  • Mitochondria- provides energy for active transport
• How are xylem cells specialised to transport water and minerals?


  • Lignin kills cells- cells won't absorb water- more efficient transport of water
  • Hollow walls- more efficient transport
  • Lignin strengthens wall- able to withstand high pressures
• How are phloem cells specialised to transport food?


  • Companion cells supply mitochondria- to keep cells alive
  • Disintegrated cell walls of cells form sieve plates- allows movement of substances to the cells
• What is differentation?

  A cell adapts to become specialised for its function.
• Animal cells loose their ability to differentiate whereas plants never.
• Undifferentiated cells are called stem cells