OCR GCSE Biology A: Health, disease types and the spread and prevention of communicable disease (J247) – Revision Notes

These notes condense statements B6.3a to B6.3e of the OCR GCSE (9-1) Gateway Science Biology A (J247) specification, Version 4.0 (August 2026), Topic B6 Global challenges. All five statements are assessed in both Foundation and Higher Tier papers. For full explanations, read the study guide. Then test yourself with the practice questions. Course pages: OCR GCSE Biology hub, checklist and free diagnostics.

Key terms

Term	Meaning
Pathogen	A micro-organism (virus, bacterium, protist or fungus) that causes disease
Communicable disease	A disease that can be passed from one host to another
Non-communicable disease	A disease that cannot be passed on
Vector	A living carrier, such as a mosquito, that moves a pathogen between hosts
Antigen	A molecule, often a protein on a pathogen, that the immune system recognises as foreign
Incidence	Number of new cases in a population in a set time, often per 100 000
Quarantine	Keeping people, animals or plants that might be infected apart, or stopping them entering an area
Sample	A small, ideally random, part of a population used to estimate the whole

Health and disease (B6.3a)

• Health = physical, mental and social wellbeing, not just being free of disease.
• Disease lowers health. Poor health (poor diet, stress, little sleep) raises the chance of disease.
• A long disease can affect all three parts: pain (physical), worry (mental), missed work or school (social).

Types of disease (B6.3b)

	Communicable	Non-communicable
Cause	Pathogen	Genes, diet, lifestyle, environment, ageing
Spread between hosts?	Yes	No
Examples	Influenza, cholera, malaria, athlete’s foot	Cystic fibrosis, scurvy, many cancers, type 2 diabetes

Non-communicable groups to name: inherited, deficiency, lifestyle-related, mental illness, most cancers.

Must-know distinctions

• Inherited (genes passed on) is not the same as communicable (pathogen passed on).
• Cancer is non-communicable, and mostly not inherited.
• Plants also have both types: a virus infection versus a mineral deficiency.

Interactions (B6.3c)

Pair	Direction	Reason in one line
HIV and TB	Virus makes bacterial disease more likely and worse	Weakened immune system fights TB bacteria less well
HPV and cervical cancer	Communicable disease can cause a non-communicable one	Long-lasting infection changes cervical cells so they divide uncontrollably

Other links: malnutrition weakens defences; long illness can cause low mood.

Method for an “interaction” answer

1. Name both diseases.
2. Say which one affects the other.
3. Give the mechanism in one clause.

Spread (B6.3d)

Pathogen	Example	Route
Virus	Influenza	Droplets in the air
Bacterium	Cholera	Contaminated water and food
Protist	Malaria	Mosquito vector
Fungus	Athlete’s foot	Direct contact, damp shared floors

• Vector = organism that carries a pathogen without being harmed. It is not the pathogen.
• Plant routes: contact (hands, tools), wind-blown spores, water splash, soil, insects, imported plants.
• Faster spread: crowding, poor sanitation, warm damp climate, no immunity.

Why some outbreaks grow faster

• Crowded hosts: classrooms, hospital wards, plants grown close together.
• Poor sanitation: sewage reaching drinking water.
• Warm, wet weather that suits fungal spores and mosquito breeding.
• A large pool of hosts with no immunity.
• Movement of people, livestock and plants across borders.

Link each factor to a route when you answer. “Crowding” alone is weak; “crowding means droplets reach more people” is complete.

Reducing and preventing spread (B6.3e)

Break the link by	Example
Stopping contact	Hand washing, isolation of cases
Cleaning water and food	Sewage treatment, safe storage
Controlling vectors	Nets, insecticide, drain standing water
Protecting plants	Remove and destroy infected plants, quarantine imports, clean tools, rotate crops, fungicide, resistant varieties

Matching control to route: quick drill

Situation	Best control	Why
Diarrhoeal disease after flooding	Clean drinking water, boiling, sewage treatment	The route is contaminated water
Malaria in a village	Nets, insecticide, drain stagnant pools	The route is the mosquito
Flu on a hospital ward	Isolation, hand hygiene, covering coughs	The route is droplets and contact
Fungal leaf spot in a greenhouse	Remove infected leaves, space plants, spray fungicide	Spores move leaf to leaf
Virus on tomato plants	Disinfect tools and hands, destroy infected plants	Virus spreads by contact and no spray cures it

Detection methods

Method	What it finds	Weakness
Visual identification	Symptoms such as rash, spots, mosaic leaves	Different causes look alike; some hosts show nothing
Antigen detection	A pathogen protein in a sample	Needs a suitable test for each pathogen
DNA testing	Pathogen DNA, so species or strain	More equipment and time

Early detection means early isolation, treatment and contact tracing.

Number skills

Skill	Formula	Mini example
Bacterial growth	start × 2ⁿ (n = divisions)	5 cells, 6 divisions: 5 × 64 = 320
Estimate cases	(sample positives ÷ sample size) × population	14 of 200 in 2000 people: 0.07 × 2000 = 140
Incidence	cases ÷ population × 100 000	120 cases in 40 000: 300 per 100 000
Percentage change	(old − new) ÷ old × 100	50 to 30: 40% decrease

Method for reading a scatter diagram

1. Describe the trend: positive, negative or none.
2. Say how strong it is (points close to a line, or scattered).
3. Do not claim cause unless a biological reason is given; mention other factors.

Worked reminders: interpreting data

Bar chart of cases. Read the values from the axis, state the highest and lowest, then compare using numbers. For example, “Ward A fell from 9 to 4 cases, a fall of 5 cases or 56%” scores better than “Ward A went down a lot”.

Table before and after an intervention. Compare like with like. Convert to a percentage change or a rate if the groups are different sizes. Then ask whether anything else changed: season, staffing, weather.

Evaluating a control method. Give one strength, one limit and a judgement. For example, mosquito nets are cheap and protect sleeping people, but they do nothing against bites during the day, so they work best alongside draining breeding sites.

Scatter diagram. Quote two data points to show the trend, such as “at 20 vectors there were 5 cases and at 80 vectors there were 24”.

Command words for this unit

• Describe: say what happens or what the relationship is, with no reasons needed.
• Explain: give a reason, linking cause to effect, often with “because” or “so”.
• Suggest: apply what you know to a new situation, for example an unfamiliar disease.
• Evaluate: weigh strengths against limits and reach a judgement using the evidence given.
• Calculate: show the working line, give the unit and check the size of the answer is sensible.

For a spread question, a reliable structure is pathogen, route, why that route works. For a prevention question it is route, method, how the method breaks the route.

Quick self-test

1. State the three parts of health.
2. Give two non-communicable diseases that are not caused by a pathogen and are not inherited.
3. Explain why a person with HIV is more at risk from TB.
4. Name the disease that HPV can cause, and say whether that disease is communicable.
5. Name the vector and the pathogen group for malaria.
6. Give two ways a plant fungus can spread between plants.
7. A town of 3000 people. A random sample of 150 finds 12 infected. Estimate the number infected.
8. Calculate incidence per 100 000 for 45 cases in 25 000 people.
9. Name three methods of detecting a plant or animal disease.
10. Cases fall from 80 to 52 after hand washing is introduced. Calculate the percentage decrease.

Answers

1. Physical, mental and social wellbeing.
2. Any two from: scurvy or other deficiency disease, type 2 diabetes, many cardiovascular diseases, many cancers, mental illness.
3. HIV weakens the immune system, so the body fights the TB bacteria less well and infection is more likely to take hold or become active.
4. Cervical cancer; it is non-communicable.
5. Vector: mosquito. Pathogen group: protist.
6. Any two from: wind-blown spores, water splash, contact on tools or hands, contaminated soil, imported infected plants.
7. 12 ÷ 150 = 0.08; 0.08 × 3000 = 240.
8. 45 ÷ 25 000 × 100 000 = 180 per 100 000.
9. Visual identification, antigen detection, DNA testing.
10. (80 − 52) ÷ 80 × 100 = 35%.

Where marks are usually lost

• Defining health as “not being ill”.
• Saying cancer or a deficiency disease can be “caught”.
• Naming the mosquito as the pathogen, or saying a vector “causes” the disease.
• Writing “HIV causes TB”. HIV makes TB more likely; the bacterium causes TB.
• Giving a control method that does not match the route.
• Forgetting units or “per 100 000” with incidence.
• Giving an estimated number of cases without noting it is an estimate from a sample.
• Describing a scatter graph’s trend but then claiming it proves cause.
• Matching treatment to the wrong pathogen group, such as suggesting a fungicide for a bacterial infection of an animal.

Official syllabus

OCR GCSE (9-1) Gateway Science Biology A (J247), Version 4.0 (August 2026), for first assessment in 2018, published by OCR. Statements B6.3a to B6.3e.