6.5Chapter 6: Nutrition, Health and Movement

Diet, growth and development — Alhussan Biology - Stage 8 Revision Notes & Topical Questions

5 min read 7 parts Lesson 5 of 12 2 quizzes

📚 Alhussan Biology - Stage 8 Hub / Topical Revision

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Lesson summary

Biology 6.5 Diet, growth and development — Alhussan International Academy — Biology (Stages 7–9) notes: Explain how a lack of vitamins and minerals causes deficiency diseases and name the functions, sources and symptoms.Lifestyle — each person has an individual lifestyle, and fac…

Balanced diet
Small amounts
Vitamin D and calcium
Respiration
Non-infectious
Night-blindness

Part 1 of 5Diet, lifestyle and deficiency

Lifestyle

Lifestyle each person has an individual lifestyle, and factors including diet affect every stage of life.

Balanced diet

Balanced diet everyone needs one for the body to function properly.

Deficiency disease

Deficiency disease an illness caused by lacking one component of a balanced diet.

It affects growth, development and health in children and overall health in adults.

Pregnancy

Pregnancy if a pregnant woman is malnourished, the development of her baby may be affected before it is born.

Small amounts

Small amounts only tiny amounts of vitamins and minerals are needed, but if any is missing a deficiency disease results.

Part 2 of 5Vitamin deficiencies

Vitamin A

Vitamin A needed for healthy eyes, especially seeing in dim light.
Sourcesegg yolks, fish liver oils, dairy products, green vegetables, apricots and carrots.
Deficiencynight-blindness, where the eyes are damaged and cannot see in dim light.

Vitamin C

Vitamin C helps cells stick together in the skin and takes part in the reactions of aerobic respiration.
Sourcescitrus fruits such as oranges, lemons and limes, and tomatoes.
Deficiencyscurvy, with bleeding gums, peeling skin, swollen legs and stopped aerobic respiration, which is eventually fatal.

Vitamin D

Vitamin D helps bones absorb the calcium they need to be hard and strong.
Sourcesfish liver oils, egg yolks and cream, and the skin makes it in sunlight.
Deficiencyrickets, where the bones of growing children cannot absorb calcium, so they are soft and bendy and curve outwards.
In children and adults the bone structure is weakened and teeth crumble away.

Part 3 of 5Mineral deficiencies

Calcium

Calcium needed for strong, healthy bones and teeth.
Sourcesdairy products such as milk, yoghurt and cheese.
Deficiencyweak, crumbly bones and teeth, and rickets.

Iron

Iron needed for the haemoglobin in red blood cells, which picks up oxygen in the lungs and carries it to cells for aerobic respiration.
Sourcesred meat, egg yolks, liver, apricots and green leafy vegetables.
Deficiencyanaemia, where red blood cells lack haemoglobin and fewer are made, so the person looks pale and feels tired and weak.

Nutrient	Function	Source	Deficiency disease
Vitamin A	Healthy eyes, sight in dim light	Carrots, liver, green vegetables	Night-blindness
Vitamin C	Holds cells together, helps respiration	Citrus fruits, tomatoes	Scurvy
Vitamin D	Helps bones absorb calcium	Fish liver oil, egg yolks, sunlight	Rickets
Calcium	Strong bones and teeth	Milk, yoghurt, cheese	Rickets, weak bones
Iron	Makes haemoglobin	Red meat, liver, green leafy vegetables	Anaemia

Part 4 of 5Links between deficiencies

Vitamin D and calcium

Vitamin D and calcium both lack of vitamin D and lack of calcium cause rickets,
- because bones need vitamin D to absorb calcium even if enough is eaten.

Respiration

Respiration scurvy and anaemia both affect aerobic respiration in cells.
In scurvy cells stop sticking together and respiration stops, so tissues break down.
In anaemia less oxygen reaches the cells, so aerobic respiration slows, causing tiredness.

Part 5 of 5Cures and prevention

1Cure

Cure eat foods containing the missing nutrient or take supplements.

2Sunlight

Sunlight people who stay indoors in places with little sun may need vitamin D in their diet.

3History

History sailors on long voyages without fresh fruit suffered scurvy until citrus juice was added to rations,
- and rickets was common in smoky cities with little sunlight.

4Today

Today fortified foods, such as flour with added iron, help prevent deficiencies.

5Non-infectious

Non-infectious deficiency diseases are not infectious and are preventable with a varied diet.

Key terms

Term	Meaning
Deficiency disease	An illness caused by a lack of a nutrient.
Scurvy	A disease caused by lack of vitamin C.
Rickets	A disease of weak bones caused by lack of vitamin D or calcium.
Anaemia	Too few red blood cells or too little haemoglobin, caused by lack of iron.
Night-blindness	Inability to see in dim light, from lack of vitamin A.
Malnourished	Not receiving the right nutrients.

Avoid these mistakes

Mixing up the diseases caused by vitamins C and D — C is scurvy and D is rickets.

Saying more vitamins than needed are always better — only small amounts are needed.

Forgetting that iron is needed for haemoglobin — a shortage causes anaemia.

Thinking deficiency diseases are infectious — they are caused by a lack of a nutrient.

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Last updated: 13 October 2026