Blood cell infected with malaria parasite

Malaria is caused by the single-celled parasite Plasmodium. It is transmitted from one person to another by certain species of blood sucking mosquito. The parasite spends part of its complex life cycle inside red blood cells.

More about microbes

Revision tips

Key facts and important ideas that will help with last minute revision about microbiology.

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Bacterial cells don’t have a NUCLEUS or any other membrane bound organelles. Their genetic information is contained in a single loop of DNA.

No - antibiotics can only be used to treat bacterial infections. They work by interfering with the bacterium’s metabolism. They can’t be used to treat viral infections, as viruses don’t have a cell wall.

Remember: Not to confuse antibodies with antibiotics. Antibiotics are chemicals made by microbes that kill or inhibit bacteria. Antibodies are proteins made by white blood cells in response to a specific antigen (pathogen).

A pathogen is a microbe that causes disease.

White blood cells called phagocytes engulf invading microbes using pseudopodia. The phagocyte then releases digestive enzymes, which break down the trapped microbe before it can do any harm. This is a non -specific defence mechanism.

White blood cells called lymphocytes recognize the pathogen (antigen) as foreign and produce antibodies that are specific to that antigen. The antibodies destroy the antigen, which is then engulfed by macrophages. This is the immune response.

Remember: A pathogen is a micro-organism that has the potential to cause disease. An infection is the invasion and multiplication of pathogenic microbes in an individual or population. Disease is when the infection causes damage to the individual’s vital functions or systems. An infection does not always result in disease!

Green algae just like green plants use chlorophyll to trap light energy. They use this energy to change carbon dioxide and water into sugar and oxygen. This is called photosynthesis.

The best way to prevent food poisoning is to follow good kitchen hygiene rules. Store food correctly in the refrigerator so that raw food isn’t next to cooked food to reduce the risk of cross contamination, wash hands before and after handling food and cook raw meat and poultry thoroughly.

When living organisms die some soil bacteria and fungi called the decomposers break them and their waste products down into simpler substances called nutrients. For example, protein is broken down into nitrites and then nitrates which are reusable by plants.

Spirogyra use light energy from the sun to convert carbon dioxide in to sugar. It makes its own food and is at the start of the food chain. It is a primary producer.

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