B1.4

• Nerve cell adaptions


  Long axon to transfer electrical impulses at great lengths.

  Axon covered in myelin sheath to insulate it and speed up the impulses.

  Many dendrites to increase surface area and make it easier to connect to other nerve cells.

  Synapses allow electrical impulses to move from on nerve cell to another.
• Sperm cell adaptations


  Tail that whips side to side to move through female reproductive system and water

  Acrosome containing digestive enzymes to break the protective coats of the egg cell.

  Middle section filled with mitochondria that releases energy for the cell to function

  Large nucleus contain half the amount of DNA for fertilisation.
• Muscle cell adaptations

  Special proteins that slide over each other in order to make the muslce contract.

  Packed with mitochondria that releases energy which can be used by the protein fibres to contract and relax.

  Can store glycogen which is broken down via cellular respiration to provide energy by the mitochondria.
• • Most types of animal cell differentiate at an early stage.
• In mature animals, cell division is mainly restricted to repair and replacement.