Are all the cells same? Abid Raza PrepI-C 30th July 2009

Why are cells different? Some animal and plant cells are made of just one cell, or just few cells. All of their cells have to carry out all the processes of life. However, large organisms are more complicated and they have different organs to do different jobs. The shape and structure of each cell help each one to do its Job properly.

Specialised Cells Humans are made of lots of cells, not just one cell. The cells in many multi-cellular animals and plants are specialised, so that they can share out the processes of life. They work together like a team to support the different processes in an organism.  We say the cells are specialised because they have special structure for special function. Red Blood Cell Sperm Cell Egg Cell Nerve Cell Epithelium Cell Root Hair Cell

Red Blood Cell The red blood cell of our blood comes from the millions of red blood cells which it contains. They carry oxygen from the air In the lungs to all the body cells. The body needs a lot of oxygen so the red blood cell has no nucleus. This gives it space to carry as much oxygen as possible.

Nerve Cell Nerve cell carry messages around your body. Example, if you want o move your hand, your brain sends a message through a nerve cell to your hand telling it to move. Nerve cells are very long so they can carry messages a long way. They are also branched at the ends to pick up and deliver messages from places to places

Epithelium Cells These cover and protect the surface of organs. They are Usually flat and fit together in sheets to cover the organs properly.

Root Hair Cell You can see these on the roots of plants. Since they are very long and thin, they can take in a lot of water from the soil.