Lets take a look at typical animal cells

Nucleus Cytoplasm Membrane Animal Cells

These join together to form different parts of the body. Animal Cell

When cells join together they form tissues. There are muscle and nerve tissues. They have different functions. This is some muscle tissue taken from the human heart.

When tissues join together they form organs. The heart is an organ.

Another example of an organ is the lung. This is an airway in the lung.

So what are the lungs there for? The Lungs deliver oxygen to the blood. The blood takes the oxygen to the muscles. Oxygen is turned into energy.

Another example of an organ is the lung. When we breath in air travels down our airways. These airways contain epithelial cells, which have tiny hairs to trap dirt and dust. The cells line the airways.

Diagram of epithelial cells Nucleus Membrane Cytoplasm Epithelia

Lets have a look at some blood cells. I hope no ones squeamish! So oxygen ends up in the blood… Do you notice the lack of a nucleus? That shadow in the middle of the cell is NOT a nucleus! The cell has a curved shape.

But does something look wrong with this picture!???

Ahh that’s better! Red blood cells:

Red blood cells have their characteristic red colour because of a chemical called haemoglobin. It is red in colour and is very good at combining with oxygen molecules. Red blood cells:

White blood cells are not white (they are actually colourless!). They fight disease in the body. White blood cells:

Notice the strange shape of the nucleus? It is almost in two completely separate parts. There are different types of white blood cells. White blood cells:

There are not as many white blood cells as red blood cells. Here are some more pictures. White blood cells:

There is about one white blood cell to every one hundred red blood cells. White blood cells:

We can only see the nucleus and cell in these pictures because they have been stained with a purple dye. White blood cells:

Now one reason we are here... So what are they?

When an egg cell meets with a sperm cell, fertilisation takes place. Egg cell Sperm Cell

When an egg cell meets with a sperm cell, fertilisation takes place. Okay, so they don’t look like much!

But they are responsible for you. It takes only one sperm and one egg. Each sperm is in fierce competition to fertilise the egg. Like being the winner of a marathon!

So to summarise. ALL of the life on this planet is made up of CELLS. Cells are alive!

Now some little forms of life you don’t see every day...

These are single celled organisms. Too small to see without a powerful microscope