AQA GCSE Combined science Biology - infection and response

infection and response Paper 1

What is a pathogen?

A microorganism that causes disease.

Name the four main types of pathogens.

Bacteria, viruses, fungi, and protists.

How do bacteria cause disease?

By producing toxins that damage cells and tissues.

How do viruses cause disease?

By entering cells and replicating, causing the cells to burst.

Give an example of a bacterial disease.

Salmonella

Give an example of a viral disease.

Measles or HIV.

Give an example of a fungal disease.

Rose black spot

Give an example of a disease caused by a protist.

Malaria

How is malaria spread?

By a vector (mosquito) through bites.

How is the spread of malaria reduced?

Using mosquito nets and killing mosquitoes.

What are the symptoms of salmonella?

Fever, stomach cramps, vomiting, and diarrhoea.

How is salmonella controlled in the UK?

Poultry are vaccinated against it.

What are the symptoms of measles?

Fever and red skin rash.

How is HIV transmitted?

Through sexual contact or exchange of body fluids.

What does HIV damage in the body?

The immune system (can lead to AIDS if untreated).

What are the symptoms of rose black spot?

Purple or black spots on leaves, which turn yellow and drop off.

How is rose black spot treated?

Removing infected leaves and using fungicides.

What is the body’s first line of defence against pathogens?

Skin, nose hairs, mucus, stomach acid.

How do white blood cells defend against pathogens?

By engulfing them (phagocytosis), producing antibodies, and producing antitoxins.

What is a vaccination?

Injecting a small amount of dead/inactive pathogen to stimulate the immune response.

How do vaccinations prevent illness?

They stimulate the production of memory cells and antibodies.

What is an antibiotic?

A drug that kills bacteria but not viruses.

Why can’t antibiotics treat viral infections?

Viruses live inside cells, making them hard to target without damaging body cells.

What is antibiotic resistance?

When bacteria mutate and no longer respond to antibiotics.

How can antibiotic resistance be reduced?

Only using antibiotics when necessary and completing courses of medication.