AQA Combined Science Biology Paper 1 - Infection and Response

Flashcards for AQA Combined Science Biology Paper 1 on the topic of Infection and Response, covering key concepts and definitions.

What is a pathogen?

A microorganism that causes disease.

Name the four main types of pathogens.

Bacteria, viruses, fungi, protists.

How are pathogens spread?

Air (droplets), water, direct contact.

Name a bacterial disease in humans.

Salmonella or gonorrhoea.

What are the symptoms of salmonella?

Fever, stomach cramps, vomiting, diarrhoea.

How is gonorrhoea treated?

Antibiotics (penicillin), barrier contraception.

Give an example of a viral disease in humans.

Measles or HIV.

What is TMV and what does it affect?

Tobacco Mosaic Virus, affects plants, causes discolouration.

Give an example of a fungal disease in plants.

Rose black spot.

Name a disease caused by a protist.

Malaria.

Name 3 non-specific defences of the human body.

Skin, nose hairs, stomach acid.

What are the three ways white blood cells fight pathogens?

Phagocytosis, antibody production, antitoxin production.

How do vaccines work?

Inject dead/inactive pathogens to stimulate antibody production.

What is herd immunity?

When a large percentage of a population is vaccinated, reducing spread.

Why don’t antibiotics work on viruses?

Viruses live inside cells, so antibiotics can’t reach them.

What is antibiotic resistance?

When bacteria mutate and are no longer killed by antibiotics.

Where did aspirin originally come from?

Willow tree bark.

What is the purpose of a double blind trial?

Neither the patient nor doctor knows who receives the drug or placebo — avoids bias.

What are the three stages of drug testing?

Lab testing (cells/tissues), animal testing, clinical trials (humans).

What is the role of white blood cells in the immune system?

White blood cells, or leukocytes, protect the body against infections by identifying and destroying pathogens.

How does vaccination provide immunity?

Vaccination introduces a harmless form of a pathogen to stimulate the immune system, leading to the production of memory cells that confer immunity against future infections.

What factors contribute to antibiotic resistance?

Antibiotic resistance develops due to overuse of antibiotics, incomplete courses of treatment, and misuse of antibiotics in agriculture.

What is the life cycle of the malaria parasite?

The malaria life cycle involves a mosquito vector, which transmits the parasite to humans, where it multiplies in the liver and red blood cells, causing sickness.

How do viruses and bacteria differ?

Viruses are non-living entities that require a host to replicate, while bacteria are single-celled organisms that can live independently.

What function do antibodies serve in the immune response?

Antibodies bind to specific antigens on pathogens, neutralizing them and marking them for destruction by other immune cells.

Why is a control group important in an antibiotic effectiveness experiment?

A control group is necessary to establish a baseline for comparison, ensuring that observed effects are due to the antibiotic and not other variables.