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. This allows them to carry out specific functions
• Most differentiation occurs as an organism develops. In most animal cells, the ability to differentiate is then lost at an early stage, after they become specialised. However, lots of plant cells don't ever lose this ability
• The cells that differentiate in mature animals are mainly used for repairing and replacing cells, such as skin or blood cells
• Some cells are undifferentiated cells - they're called stem cells
• Examples of specialised cells: Sperm cells, nerve cells, muscle cells, root hair cells, phloem and xylem cells
• Sperm cells are specialised in reproduction
• The function of a sperm cell is to get the male DNA to the female DNA.
• Sperm cells have a long tail and a streamlines head to help it swim to the egg
• There is a lot of mitochondria in a sperm cell to provide the energy needed
• Sperm cells also carry enzymes in its head to digest through the egg cell membrane
• Nerve cells are specialised for rapid signalling
• The function of nerve cells is to carry electrical signals from one parts of the body to another
• Nerve cells are long (to cover more distance) and have branched connections at their ends to connect to other nerve cells and form a network throughout the body
• Muscle cells are specialised for contraction
• The function of a muscle cells is to contract quickly
• Muscle cells are long ( so that they have space to contract ) and contain lots of mitochondria to generate energy
• Root hair cells are specialised for absorbing water and minerals
• Root hair cells are on the surface of plant roots, which grow into long hairs that stick out into the soil
• Root hairs cells are given a large surface area for absorbing water and mineral ions from the soil
• Phloem and xylem cells are specialised for transporting substances
• Phloem and xylem cells form phloem and xylem tubes, which transport substances, such as food and water around plant
• To form the phloem and xylem tubes, the cells are long and joined end to end
• Xylem cells are hollow in the centre and phloem cells have very few subcellular structures, so that stuff can flow through them