By using microscopes, scientist have shown that cells are the buildings blocks of all living things. Some living things are made up of only one cell. Other have many cells.

Inside of living cells there are many parts. Each part has a particular function or job to do.

Animal cells

All living things are made of of cells, including animals. Cells have tiny organs known as organelles. Each of these tiny organs have a special function. We can only see an organelles under a microscope.

Cell organelles that can be seen with a light microscope.

• Nucleus- the control center of the cell. It controls all the chemical reactions in the cell, how the cell develops and how it reproduces. 9
• Cell membrane- The ‘skin’ that holds the cell together. It controls what comes into and leaves the cell.
• Cytoplasm-a watery, jelly-like mixture that contains many smaller parts where the world of the cell takes place
• Vacuole- there may be several very small vacuoles in animal cell. They may contain wastes or chemicals that are being moved around the cell

Only found in Plant cells

• Chloroplast- chloroplasts are only found in plant cells and only in the green parts of plants. Chloroplasts are the site of photosynthesis
• Cell wall- plants do not have skeleton, so they need something else to keep them upright and to keep their shape. This is the function of the cell wall, which lies outside the cell membrane.

Electron microscopes help us see even smaller organelles such as:

• Mitochondria are the powerhouses of the cell, which release energy from food
• Lysosomes are the garbage disposal units that get id of wastes from the cell
• Endoplasmic reticulum forms pathways that allow materials to move quickly and easily through the cell

List of animal cells organelles

• Nucleus
• Cell membrane
• Vacuole
• Cytoplasm

List of plant cell organelles

• Nucleus

• Cell membrane

• Vacuole

• Cytoplasm

• Chloroplasts

• Cell wall

Fungal cells

Fungi are a group of organisms that can be made of just a single cell ( such as yeast) or many cells such as a toad stool.

Cells of fungi have the same parts of animal cells. Fungal cells also have a cell wall like a plant cell. However plant and fungal cell walls are made of different chemicals. Fungal cells do not have chloroplasts , therefore they cannot make their own food.

Fungi produce substances that digest the material they are growing on. They then absorb the digested materials into their cells.

Unicellular organisms

Unicellular organisms are living things that are only made of one cell.

Examples of unicellular organisms include:

• bacteria (Cholera and Salmonella)
• Yeast
• Protists (Giardia lamblia)

Unicellular organisms live in watery environments. A drop of pond water seen through a microscope can reveal a variety of living things you will not have seen before.

Many different types of unicellular organisms live in watery environments. A drop of pond water seen through a microscope can reveal a variety of living things you will not have seen before, like the diatoms and rotifers.

Most protists are harmless, but some can make you very sick. For example, giardia is an infection caused by the protist Giardia lamblia. This unicellular organism is found in the faeces of humans and other animals. A person becomes infected when they swallow the parasite from their unwashed hands or drink infected water. The water that comes through the taps has been treated to kill any harmful organisms such as Giardia. If you are in the bush and using untreated water, then for your health’s sake it is best to boil the water before you drink it.

Dividing cells

Unicellular organisms reproduce by their cell dividing to produce two new identical cells, that is, two new organisms, this type of cell division is called mitosis. Mitosis is cell division that produces two new identical-cells.

Mitosis is important because it allows multicellular organisms to replace damaged cells and also to grow. When you cut yourself or scrape the skin off your knee, the damage is repaired by mitosis producing new cells.

Cancer is a disease caused by uncontrolled mitosis. Scientists are looking for ways of controlling cell division in these cells and hope that will help to cure the disease.