Infection and Response

What is a pathogen?

A microorganism that causes disease.

What are the four main types of pathogen?

Bacteria, viruses, fungi and protists.

What is a bacterium?

A single-celled microorganism that reproduces rapidly by binary fission.

How do bacteria cause disease?

They reproduce rapidly and may produce toxins that damage cells and tissues.

What is a virus?

A tiny pathogen that reproduces only inside living cells.

How do viruses cause disease?

They enter cells, reproduce and burst the cells.

What is a fungus?

A pathogen that can be single-celled or multicellular and often reproduces by spores.

How do fungi cause disease?

They spread through tissues and produce enzymes that damage cells.

What is a protist?

A single-celled eukaryotic organism, some of which are pathogens.

Name a disease caused by protists.

Malaria.

How can pathogens spread?

Through air, water, direct contact or vectors.

What is a vector?

An organism that carries pathogens from one host to another.

What causes communicable diseases?

Pathogens.

What causes non-communicable diseases?

Genetic, lifestyle or environmental factors.

What is salmonella?

A bacterial food poisoning infection.

How can salmonella be prevented?

Vaccinating poultry, good hygiene and thorough cooking.

What are the symptoms of salmonella?

Fever, stomach cramps, vomiting and diarrhoea.

What causes gonorrhoea?

Bacteria.

How is gonorrhoea spread?

Sexual contact.

How is gonorrhoea treated?

Antibiotics.

Why is gonorrhoea becoming harder to treat?

Some bacteria have become antibiotic resistant.

What causes measles?

A virus.

How is measles spread?

Droplets from coughs and sneezes.

What are the symptoms of measles?

Fever and a red skin rash.

How can measles be prevented?

MMR vaccination.

What causes HIV?

A virus.

How does HIV damage the body?

It attacks immune cells, weakening the immune system.

How is HIV spread?

Sexual contact, infected blood or shared needles.

How can HIV be treated?

Antiretroviral drugs.

What is Tobacco Mosaic Virus (TMV)?

A virus that infects plants.

What are the symptoms of TMV?

Mosaic discolouration of leaves, reducing photosynthesis.

What causes rose black spot?

A fungus.

What are the effects of rose black spot?

Purple or black spots on leaves and reduced growth.

How can rose black spot be controlled?

Fungicides and removing infected leaves.

What causes malaria?

A protist.

How is malaria spread?

Female mosquitoes acting as vectors.

How can malaria be reduced?

Insecticides, mosquito nets and preventing mosquito breeding.

What is the body's first line of defence?

Skin and blood clotting.

How does skin protect against pathogens?

It forms a physical barrier.

How do blood clots help prevent disease?

They form scabs that stop pathogens entering.

How do tears protect the body?

They contain lysozyme enzymes that destroy bacteria.

How does stomach acid protect the body?

Hydrochloric acid kills pathogens swallowed with food.

What are white blood cells?

Cells that defend the body against pathogens.

How do phagocytes destroy pathogens?

They engulf and digest them.

What do lymphocytes produce?

Antibodies.

What do antibodies do?

They bind to specific antigens on pathogens and help destroy them.

What are antigens?

Proteins on the surface of pathogens that trigger an immune response.

What are antitoxins?

Chemicals that neutralise bacterial toxins.

What is immunity?

Protection against a disease after exposure or vaccination.

What is vaccination?

Introducing dead or inactive pathogens to stimulate antibody production.

Why are vaccinations effective?

They create memory cells for a faster immune response.

What is herd immunity?

When enough people are vaccinated to reduce disease spread.

What are antibiotics?

Medicines that kill bacteria.

Why don't antibiotics work on viruses?

Viruses reproduce inside body cells, making them difficult to target without damaging cells.

What is antibiotic resistance?

When bacteria evolve so antibiotics no longer kill them.

How does antibiotic resistance develop?

Random mutations and natural selection.

What is a painkiller?

A medicine that relieves symptoms but does not kill pathogens.

What is drug discovery?

The process of finding new medicines.

Where were many early medicines discovered?

Plants and microorganisms.

Who discovered penicillin?

Alexander Fleming.

What is penicillin?

An antibiotic produced by the Penicillium mould.

What are monoclonal antibodies?

Identical antibodies produced from a single clone of cells.

How are monoclonal antibodies used?

Pregnancy tests, diagnosis, research and targeted treatments.

What is a placebo?

A fake treatment with no active ingredient.

Why are placebos used in clinical trials?

To compare whether a medicine has a real effect.

What are the three stages of clinical drug testing?

Laboratory tests, animal testing and human clinical trials.

Why are new drugs tested?

To check they are safe, effective and the correct dose.