cell differentiation and specialisation

• cells differentiate, they develop different subcelluar structures and turn into different types of cells that allow them to carry out a specific function.

  most differentiation occurs as an organism develops, most animal cells loose this ability early after becoming specialised, most plant cells never loose this ability.

  cells differentiating in older animals are used for replacing and reparing cells (e.g skin or blood cells).

  stem cells are undifferentiated.
• specialised cell examples (sperm cells):

  specialised for reproduction

  its function is to get male dna to the female dna,

  it has a long tail and a streamlined head (help swim),

  lots of mitrocondria for energy,

  carries enzymes in its head to digest through the egg cell membrane
• specialised cell examples (nerve cells):

  specialised for rapid signalling

  its function is to carry electrical signals through the body

  its long (to cover more distance) and has branched connections at the end (to form a network by connecting to other nerve cells)
• specialised cell examples (muscle cells):

  specialised for contraction

  its function is to contract quickly

  long (for space to contract) and contains lots of mitochondria (for energy)
• specialised cell examples (root hair cells):

  specialised for absorbing water and minerals

  grow on the surface of plant roots and stick out into the soil which increases the surface area for absorbing water and mineral ions
• specialised cell examples (phloem and xylem cells):

  specialised for transporting substances

  form phloem and xylem tubes that transport substences (e.g food and water) around plants

  cells are long and join end to end to form tubes

  xylem are hollow and phloem have few subcellular structures so suff can flow through them