Specialised Cells

All cells are designed to do a particular job in an organism. This is called cell specialism. Examples of 5 specialised cells are shown below:

1) The sperm cell - designed to fertilise eggs
A sperm cell is very small and has a little tail which provides movement so it can swim and find an egg to fertilise
Its head contains enzymes (in the vacuole) which allow it to digest its way through an egg membrane so the two nuclei can join
It contains half the number of chromosomes in the nucleus - these carry genetic information from the father, which will be passed on to the offspring

2) The ovum (egg) cell - designed to be fertilised
An ovum is large and bulky because no active movement is needed - it just sits and waits for the sperm to find it
It contains yolk (in the cytoplasm) which provides a large food store needed for the developing young organism once it's fertilised
It contains half the number of chromosomes, which carry genetic information from the mother - this will be passed on to the offspring

3) The palisade cell - designed for photosynthesis
A palisade cell is tall with a large surface area
It's found on the top side of a leaf - ideal for good absorption of carbon dioxide and light - both are needed for photosynthesis
They're packed with chloroplasts, which contain the green pigment chlorophyll, which is needed for photosynthesis

4) The cilia cell - designed to stop lung damage
Cilia cells line all the air passages in your lungs
They have tiny hairs, which filter the air as it blows through
The hairs sweep mucus (snot) with trapped dust and bacteria up to the back of the throat where it is swallowed

5) The root hair cell - designed for absorbing
The long hair cell increases the surface area of the root, which helps absorption of water and minerals
It has a really thin cell wall, which makes it easier for minerals to pass across into the root itself