Cell Differentiation and Specialisation

• Differentiation is the process by which a cell changes to become specialised for its job.
• As cells change, they develop 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 the ability to differentiate
• The cells that differentiate in mature animals are mainly used for repairing and replacing cells, such as skin or blood cells
• Stem cells are undifferentiated
• Sperm cells are specialised for reproduction
• The function of a sperm is to get the male DNA to the female DNA. It has a long tail and a streamlined head to help it swim to the egg
• In a sperm cell, there are lots of mitochondria to provide the energy needed. It also carries enzymes in its head to digest through the egg cell membrane
• Nerve cells are specialised for rapid signalling
• The funtion of nerve cells is to carry electrical signals from one part 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 cell is to contract quickly and are long (so that they have space to contract)
• Muscle cells contain lots of mitochondria to generate the energy needed for contraction
• Root hair cells are specialised for absorbing water and minerals
• Root hair cells are cells on the surface of plant roots, which grow into long 'hairs' that stick out into the soil. This gives them a big surface area for absorbing water and minerals from the soil
• Xylem and Phloem cells are specialised for transporting substances
• Xylem and Phloem cells form xylem and phloem tubes, which transport substances such as food and water around plants
• To form xylem and phloem tubes, the cells are long and joined end to end
• Xylem cells are hollow in the centre whereas phloem cells have very few subcellular structures, so that stuff can flow through them