cell differentiation and specialisation

• differentiation is the process by which a cell changes to become specialised for its job
• as cells change, they develop different subcellular structures and turn into different types of cells
• most differentiation occurs as an organism develops
• the cells that differentiate in mature animals are mainly used for repairing and replacing cells
• undifferentiated cells are called stem cells
• sperm cells are specialised for reproduction
• what is the function of a sperm?

  to get male DNA to female DNA
• sperm cells have a long tail and streamlined head to help them swim to the egg
• sperm cells also carry enzymes to help them digest through the egg cell membrane
• the function of nerve cells is to carry electrical signals
• nerve cells are long and have branched connections to other nerve cells, forming a network around the body
• muscle cells are specialised for contraction
• muscle cells are long and contain lots of mitochondria to generate the energy needed for contraction
• root hair cells are specialised for absorbing water and minerals
• root hair cells give plants a big surface area for absorbing water and mineral ions from the soil
• phloem and xylem cells are specialised for transporting substances
• phloem cells transport food around plants
• xylem cells carry water around the plant
• xylem cells are hollow in the centre
• phloem cells have very few subcellular structures