4.1.1.3 cell specialisation

• what are the specialised cells in animals?

  sperm cells, nerve cells and muscle cells
• what are the specialised cells in plants?

  root hair cells, xylem and phloem
• How are nerve cells specialised?

  To carry electrical impulses around the body which provides a rapid communication between different parts of the body
• how are nerve cells specialised?

  they have:

  • Lots of dendrites to make connections to other nerve cells
  • an axon that carries the nerve impulse from one place to another
  • Nerve endings that are adapted to pass the impulses to another cell - they contain lots of mitochondria to provide energy
• how are muscle cells specialised?

  they can contract and relax to enable movement in the body
• what are the main adaptations of striated muscle cells?

  
  

  • They contain special proteins that slide over each other making the fibres contract
  • They contain lots of mitochondria to transfer the energy needed for the chemical reactions that take place as they contract and relax
  • They can store glycogen
• How are sperm cells specialised?

  They carry genetic information from the male to the female to fertilise the egg cell
• what adaptations does a sperm cell have?

  w

  • A long tail that helps it to move
  • The middle section is full of mitochondria which transfer energy for the tail to work
  • The acrosome stores digestive enzymes for breaking down the outer layers of the egg
  • A large nucleus contains the genetic material to be passed on
• how are root hair cells specialised?

  to help the plant take up water and mineral ions more effectively
• what are the main adaptations on a root hair cell?

  • They increase the surface area available for water to move in or out the cell
  • They have a large permanent vacuole that speeds up the movement of water by osmosis
  • they have many mitochondria that transfer they energy needed for active transport
• what is a xylem?

  the xylem is the transport tissue in plants that carries water and mineral ions from the roots and also supports the plant
• how are xylem cells adapted to function?

  • they are not living and don’t contain a cytoplasm or nucleus
  • The cells form hollow tubes that hold water for transport
  • The lignin is waterproof and rough
  • The cell wall and membranes don’t exist on the end of the cells to connect them together
• what is phloem?

  the transport tissue that carries food made by photosynthesis around the body of the plant
• how are phloem cells adapted?

  • The cell walls between the cells break down to form sieve plates which allow water carrying dissolved food to move freely up and down
  • They are supported by companion cells which have lots of mitochondria