Microbes

Bacteria e.g. Salmonella and Tuberculosis (TB)

Size: 1/1000 mm

Shape: Bacteria can be spherical, rod-shaped or cone-shaped.

Structure: Bacteria are single-celled organisms, which do not completely have a nucleus. Some cause disease but many are useful.

Reproduction: Bacteria reproduce very quickly. Two can very quickly become 4, then 8 and so on.

Viruses e.g. Flu and HIV

Size: 1,000,000 mm

Shape: Regular geometric shapes

Structure: A virus is a simple organism which does not display all the characteristics of living things. They are made up of a protein coating and some genetic material.

Reproduction: Viruses and only reproduce within other living things.

Fungi e.g. Thrush and Athlete's foot

Size: Some can be seen with the naked eye.

Shape: Fungi come in many different shapes.

Structure: Fungi have the most complex structuren of all the microbes. They feed off other living things.

Microbes have many uses:

Bacteria grow in milk to make it "go off".

• This type of bacteria growth is used to turn milk into yogurt
• Cheese is another product made from milk

Fungi is also used to make food.

• The meat substitute Quorn is a protein made from fungi
• Yeast is a type of fungus that carries out respiration. This respiration can be used in different ways in making bread and in brewing.

1) Transmission by air

A cough or a sneeze can release millions of microbes in the air which then infect someone else.

2) Transmission by water

Dirty water can transmit many diseases e.g. cholera

3) Transmission by animals

An animal can carry a microbe from one place to another e.g. mosquitos spread the malaria parasite.

4) Transmission by contact

Microbes can be exchanged by direct or indirect contact. Direct contact includes contact by hand and indirect contact includes walking on a wet floor already contaminated by someone contaminated by athlete's foot.

• antibiotics - Chemicals prescribed as a medicine to kill bacteria inside the body.

• antibodies - Chemicals produced by white blood cells to fight microbes.

• bacteria - The type of microbes that are single-celled organisms.

• fungi - The type of microbes that feeds off other living things.

• immune - Resistance to infection caused by a microbe.

• microbe - A very small living thing.

• transmission - The spread of disease from person to person.

• viruses - The types of microbe that only grows and reproduces withing other living things