Microorganisms & Disease

All life on Earth consists of cells. Some living things contain millions of cells and others contain only 1 cell.

A Microorganism is a living thing that can only be observed using a microscope. Most microorganisms contain only 1 cell. There are millions of different types of microorganisms, many have a positive effect on our lives but some can have negative effects, such as cause diseases.  

Types of Microorganisms

There a millions of different microorganisms on Earth, but all can be described in four main groups:-


Bacteria

The diagram below shows the three main shapes of Bacteria:-

The audio file below is a track from Jeff Wayne's War of the Worlds, based upon H.G. Wells classic novel. 

As can be seen from the above audio clip, bacteria are microorganisms which can cause diseases. However, bacteria have many more functions, most of which have nothing to do with us at all! 

The functions of bacteria include:-

There are thousands of other beneficial things that bacteria do, without which the Earth would look very different!

Diseases caused by bacteria include:-

Bacteria Case Study : Cholera

Cholera is a bacterial infection that can be caused by drinking contaminated water, or eating contaminated food. Cholera causes severe diarrhoea, stomach cramps and nausea and kills over 140,000 people a year worldwide. Cholera kills due to the severe vomiting and diarrhoea causes the infected person to become severely dehydrated, which can be fatal if not treated.  

The treatment for cholera is Oral Rehydration solutions. These are solutions that contain a mixture of Glucose (sugar) and salts, which when drank acts to replace the fluids and minerals lost due to Cholera. This allows the body enough time to fight off the Infection itself. 

The spread of Cholera can be prevented by:-

The video below shows a short animation that shows the effects of Cholera, as well as treatment and prevention:-

Viruses

The diagram below shows the four main shapes of viruses:-

Viruses are much smaller than bacteria. Viruses are so strange that scientists are unsure if they qualify as being a living thing! Unlike most living things, viruses cannot reproduce on their own, they can only reproduce inside other cells. 

To reproduce, the virus enters a cell, then they take control of the cell, forcing it to make thousands of copies of the virus. Eventually the cell then bursts open, releasing the new viruses which can go on to infect other cells. 

Diseases caused by viruses include:-

The video below shows a detailed description of how viruses attack living cells.

Hidden life of cells.mp4

Virus Case Study : H.I.V. 

HIV (Human Immunodeficiency Virus) is a virus that attacks the body's immune system, specifically the white blood cells, which help fight off infections. Over time, HIV can weaken the immune system, making it harder for the body to fight off infections and diseases. If left untreated, HIV can lead to AIDS (Acquired Immunodeficiency Syndrome), a condition where the immune system is severely weakened to a point when any further incfections can be fatal, and was responisble for the deaths of 630,000 people gloablly in 2022. 

HIV cannot be cured, but there are very effective treatments that enable most people with the virus to live a long and healthy life. HIV is treated with antiretroviral medicines, which work by stopping the virus replicating in the body. This allows the immune system to repair itself and prevent further damage. 


The spread of HIV can be prevented by:-


The video below shows a short animation that shows the effects of HIV, as well as treatment and prevention:-

Fungi

The diagram below shows the two main types of fungi:-

Fungi are neither plants nor animals, but a class of organisms all of their own. Most people can recognise the multicellular fungi (mushrooms and toadstools), but most do not realise that the moulds that grow on food are also fungi. Fungi specialise in decay, and are vital in the decomposition of dead material, especially wood. 

Like bacteria, fungi have many more functions than causing diseases, most of which have nothing to do with us at all! 

The function of fungi include:-

There are thousands of other beneficial things that fungi do, without which the Earth would look very different!

Diseases caused by Fungi include:-

Fungi Case Study : Ringworm

Despite its name, ringworm doesn’t have anything to do with worms.

Ringworm is a common fungal infection that can cause an itchy red or silvery ring-like rash on the skin. Ringworm commonly affects arms and legs, but it can appear almost anywhere on the body. Ringworm is not serious and is usually easily treated. However, it is contagious and easily spread, including by household pets.

The spread of Ringworm can be prevented by:-

The video below shows a short animation that shows the effects of Ringworm, as well as treatment and prevention:-

Protists

The diagram below shows the three main types of protists:-

Like fungi, protists are neither plants nor animals, but a class of organisms all of their own. They all are single-celled organisms, and display similarities with animals, plants and fungi, but are too different to be counted in those groups. The plant-like protist Algae is responsible for the creation of over half the Earth's Oxygen.

Diseases caused by protists include:-

Protist Case Study : Malaria

Malaria is a serious and sometimes fatal disease caused by a parasite that is transmitted to humans through the bites of infected female Anopheles mosquitoes. It is a major global health problem, particularly in tropical and subtropical regions. The malaria parasite reproduces in red blood cells, destroying them and causing anemia, and can cause organ damage to the brain, lungs, kidneys and liver. 


The spread of Malaria can be prevented by:-

The video below shows a short animation that shows the effects of Malaria, as well as treatment and prevention:-