Cell Specialisation

Undifferentiated cells are called stem cells and can divide to produce more undifferentiated cells. They can differentiate into different types of cell, depending on what instructions they're given.

1) Stem cells are found in eary human embryos. They have the potential to turn into any kind of cell

2) Adults also have stem cells, but they're only found in certain places, like the bone marrow

3) Unlike embryonic stem cells, adult stem cells can't turn into any cell type- only certain ones

4) You can clone stem cells from embryos and the bone marrow and made to differentiate into specialised cells to use in medicine or research

Differentiation is the process by which a cell changes to become specialised for its job

1) As cells change, they develop different sub-cellular structures and turn into different types of cells. This allows them to carry out specific functions

2) Differentiation mainly occurs as an organisms develops

3) The cells that differentiate in mature animals are mainly used for repairing and replacing cells, like skin or blood cells 

Root hair cells:

• These are cells on the surface of plant roots, which grow into long 'hairs' that stick out into the soil
• This gives the plant a big surface area to absorb water and mineral ions from the soil

Sperm cells:

• Its function is to get the male DNA to the female DNA
• It has a long tail and a streamlined head to help it swim
• There are lots of mitochondria in the cell to give it the energy to swim
• It also carries enzymes in its head to digest through the egg cell membrane

Nerve cells:

• Its function is to carry electrical signals from one part of the body to another
• These cells are long (to cover more distance) and have branched connections at their end to connect to other nerve cells and form a network throughout the body

Muscle cells:

• Its function is to contract quickly
• These cells are long so that they have space to contract
• They contain lots of mitochondria to generate the energy needed for contraction