GCSE · Biology · AQA · Spec 8461

Health and disease

Can a virus passed on through sex be linked to a cancer? Yes — because diseases don't stay in their own boxes.

Health and disease

Which of these can lead to which?

Draw an arrow wherever you think one of these can make another more likely. Some of the real links are surprising, so guess boldly — then compare your web with the real one.

A damaged immune system (for example, from AIDS)
An infection by a pathogen
Cancer, such as cervical cancer
Allergies, such as skin rashes and asthma
Physical ill health
Mental ill health, such as depression
Diet, stress and life situations

Add a link

This factor……made this happen or worse

No links yet.

What does 'healthy' mean?

Is Jess healthy?

Jess hasn't got a disease of any kind. But she has been under huge stress for months, and she feels low almost every day.

Is Jess healthy? Pick the answer closest to what you honestly think.

Yes. She hasn't got a disease, so she's healthy.No. She must have a disease, or she wouldn't feel so low.Yes. Feeling low is in her head, and health is about the body.Not fully. Health includes how she feels, and stress can damage it.

How sure are you?

I'm sureI think soI'm guessing

Yes. She hasn't got a disease, so she's healthy.

This is a common misconception

It's a natural first answer — but health is more than simply not having a disease. Health is the state of physical and mental well-being, and Jess's mental well-being is clearly suffering. It also isn't all-or-nothing: picture a scale with good health at one end and ill health at the other. Jess isn't at the ill end, but she isn't at the good end either.

No. She must have a disease, or she wouldn't feel so low.

This is a common misconception

You're right that something is wrong — but it doesn't have to be a disease. Disease is one of the things that can damage health, not the only one. Diet, stress and life situations can have a profound effect on both physical and mental health, so months of stress can pull Jess down the scale with no disease involved at all.

Yes. Feeling low is in her head, and health is about the body.

This is a common misconception

Here's the catch: health includes the mind. Health is the state of physical AND mental well-being, so feeling low every day is part of Jess's health, not something separate from it. And the two sides are linked — you saw in the web that severe physical ill health can lead to depression and other mental illness.

Not fully. Health includes how she feels, and stress can damage it.

This matches the evidence

Exactly. Health is the state of physical and mental well-being — some descriptions of good health add social well-being as a third part. It sits on a scale rather than being simply present or absent, so Jess is somewhere in the middle. Disease is one thing that can damage health, in humans and in other animals and plants too; stress is another.

Health is a scale, not a switch: physical and mental well-being together. Disease can push you down that scale — but so can diet, stress and life situations.

Two families of disease

Communicable, non-communicable — or both?

Diseases come in two big families. For each card, tick the family it describes — one, both, or neither. Watch out: a couple of cards belong in the overlap.

A Communicable disease
B Non-communicable disease

Caused by a pathogen — a bacterium, virus, fungus or protist
Can pass from one individual to another
Cannot pass between organisms
Arises from lifestyle and environmental factors
Infection with HPV, a virus passed on through sex
A major cause of ill health
Your chance of getting it is changed by lifestyle, such as hygiene and diet
Stress or a difficult life situation

Maths · Reading data

New cases of an infection per 100,000 people

Four invented towns, invented numbers — for practice. Tap a bar to read its rate.

A rate 'per 100,000 people' is the number of cases for every 100,000 people who live there. Real rates are reported this way: in England in 2017 there were 9.2 new tuberculosis cases per 100,000 people. Tap a bar to see its value.

Mean

10.5

Median

10.5

Mode

Range

Exam line: Going from the graph to numbers means reading the value and saying what it means in words: 'Town B had 15 new cases for every 100,000 people.'

Watch out: The tallest bar is the highest RATE, not necessarily the most cases. A small town can have a high rate but only a handful of actual cases.

Your turn

Walk the chain in a real case

Priya has AIDS. Last year she caught tuberculosis, and she has been seriously ill for many months. She has now also been diagnosed with depression.

Describe how Priya's illnesses may be linked. [3 marks]

Your answer

0 words · your answer stays on this page and is not sent anywhere.

The mark scheme

AIDS has damaged her immune system. (1 mark)
So she could not fight off other infections, which made tuberculosis more likely. (1 mark)
Severe physical ill health, such as months of serious illness, can lead to depression. (1 mark)

Model answer

AIDS left Priya's immune system badly damaged, so her body could no longer fight off other infections — which made it more likely that tuberculosis would take hold. Months of serious illness count as severe physical ill health, and that can lead to mental illness such as depression. One disease made the next more likely, and her physical illness may have dragged her mental health down too.

In a case question, walk the chain. The case hands you the illnesses; the credit is for the connections between them — what each one did, and what it made more likely.

WHAT YOU'VE LEARNED

A quick recap of today's lesson.

Healthy isn't just 'not ill' — and one illness can open the door to another.

What you need to know

Health is the state of physical and mental well-being. It is more than simply not having a disease, and it sits on a scale between good health and ill health.
Disease is one of the things that can damage health — in humans, and in other animals and plants too.
Communicable diseases are caused by pathogens (certain bacteria, viruses, fungi and protists) and can pass between individuals. Non-communicable diseases cannot pass between organisms and arise from lifestyle and environmental factors.
Different types of disease may interact: immune defects make infectious disease more likely, viruses in cells can trigger cancers, immune reactions to pathogens can trigger allergies, and severe physical ill health can lead to mental illness.
Disease incidence can be given as a rate per 100,000 people, and you should be able to move between that number and a graph of it.

The big picture

Health is the state of physical and mental well-being, on a scale rather than simply present or absent. Disease can damage it: communicable diseases are caused by pathogens and can spread between individuals, while non-communicable diseases cannot spread and arise from lifestyle and environmental factors. Diet, stress and life situations affect health too. And diseases interact — a damaged immune system lets infections in, viruses can trigger cancers, immune reactions can trigger allergies, and severe physical ill health can lead to mental illness.

Key points

1Health = physical and mental well-being, on a scale — not an on/off switch.

2Both communicable and non-communicable diseases are major causes of ill health.

3Diet, stress and life situations can have a profound effect on both physical and mental health.

4Lifestyle, such as hygiene and diet, changes a person's chance of developing both kinds of disease.

5AIDS damages the immune system so much that other infections, such as tuberculosis, can take hold.

6HPV infection is linked to cervical cancer; a virus living in cells can be the trigger for a cancer.

7A rate per 100,000 people gives the number of cases for every 100,000 people, not the total.

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Worked example

Problem

In England in 2017 there were 9.2 new tuberculosis cases per 100,000 people. Imagine a city of 500,000 people with exactly that rate. How many new tuberculosis cases would the city have had that year?

⚠ Watch out

Writing that a virus always causes cancer. The accurate wording is that viruses living in cells CAN be the trigger for cancers — infection with HPV is linked to cervical cancer, which is not the same as saying everyone infected will get it.

🧠

Memory hook

Health is a dial, not a switch — and diseases don't stay in their own boxes. Think: a broken defence lets infections in, a virus can light the fuse for a cancer, and a body in trouble can pull the mind down with it.

✓

Check yourself

Close the page and rebuild the web from memory, starting with 'a damaged immune system'. How many arrows can you add — and say what each one does?

Flashcards

(15)

What is health?

The state of physical and mental well-being. Some descriptions of good health add social well-being too.

Is health simply present or absent?

No. A person can sit anywhere on a scale between good health and ill health.

Which living things can have their health damaged by disease?

Humans — and other animals and plants too.

What causes communicable diseases?

Pathogens: certain bacteria, viruses, fungi and protists.

What is the key difference in how the two families of disease spread?

Communicable diseases can pass between individuals; non-communicable diseases cannot pass between organisms.

What do non-communicable diseases arise from?

Lifestyle and environmental factors.

How does lifestyle, such as hygiene and diet, affect disease?

It changes a person's chance of developing both communicable and non-communicable disease.

Name three factors other than disease that can have a profound effect on physical and mental health.

Diet, stress and life situations.

What does a defect in the immune system do to a person's risk of infection?

It makes them more likely to suffer from infectious diseases.

Why is a person with AIDS more likely to get tuberculosis?

AIDS leaves the immune system so damaged that they can no longer fight off other infections, such as tuberculosis.

Which cancer is infection with HPV linked to, and how is HPV passed on?

Cervical cancer. HPV is a virus that is sexually transmitted.

What can viruses living in cells trigger?

Cancers.

What can an immune reaction first caused by a pathogen trigger?

Allergies, such as skin rashes and asthma.

What can severe physical ill health lead to?

Depression and other mental illness.

What does a disease rate 'per 100,000 people' tell you?

How many cases there are for every 100,000 people — for example, 9.2 new tuberculosis cases per 100,000 people in England in 2017.

Tap any card to flip it, or use Study as deck to go through them one at a time. In the full lesson these run as a spaced-repetition deck — you rate each card Hard, Good or Easy and the tricky ones keep coming back until they stick.

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Which of these can lead to which?

Is Jess healthy?

Communicable, non-communicable — or both?

New cases of an infection per 100,000 people

Walk the chain in a real case

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