What's covered
Key facts
Diet and nutrition
A balanced diet provides all the essential nutrients in the right amounts and proportions for the body to function healthily.
Drugs and disease
Alcohol slows reaction times, impairs judgment, damages the liver (cirrhosis) with long-term use, and increases the risk of accidents and addiction.
Exercise and health
Aerobic exercise (e.g. running, swimming) uses oxygen and can be sustained for long periods; it improves cardiovascular fitness.
Gas exchange and breathing
Alveoli are adapted for efficient gas exchange by having a large surface area, very thin (one-cell-thick) walls, and a rich blood supply.
Nutrition and digestion
Amylase is the enzyme that breaks down starch (a carbohydrate) into smaller sugars such as glucose.
Skeletal and muscular systems
Muscles work in antagonistic pairs because a muscle can only pull (contract), not push, so one muscle is needed to move a bone one way and another to move it back.
Diet and nutrition
Carbohydrates (sugars and starch) are the body's primary energy source; they are broken down to glucose which is used in respiration.
Drugs and disease
Antibiotics kill or inhibit the growth of bacteria but have no effect on viruses; taking antibiotics for a viral infection (e.g. a cold) is ineffective and contributes to antibiotic resistance.
Exercise and health
Anaerobic exercise (e.g. sprinting, weightlifting) occurs when oxygen demand exceeds supply; it produces lactic acid and can only be sustained briefly.
Gas exchange and breathing
Alveoli are the tiny air sacs at the ends of the airways in the lungs where gas exchange takes place.
Sample questions
A taste of the 66 questions in this topic, answers marked. Sign up to practise the full set with spaced repetition.
Which nutrient is a concentrated energy store and is also needed for insulation?
- ✓Fat
- •Fibre
- •Sugar
- •Water
Which of these is a physical defence that stops pathogens entering the body?
- •Antibodies made by lymphocytes
- •Memory cells from a vaccination
- •Phagocytes engulfing pathogens
- ✓Skin acting as a barrier
Why does breathing rate and depth increase during exercise?
- •To cool the body down by losing water vapour
- •To slow down the rate of respiration in cells
- •To take in extra glucose from the air
- ✓To take in more oxygen and remove more carbon dioxide
What are the tiny air sacs in the lungs called?
- ✓Alveoli
- •Bronchi
- •Capillaries
- •Cilia
What are the seven nutrients the body needs?
- •Bread, rice, meat, milk, fruit and vegetables only
- ✓Carbs, fats, protein, vitamins, minerals, fibre, water
- •Just carbohydrates, fats, and protein content only
- •Sugars, salts, oils with some fibre included
What is the female sex cell in humans called?
- ✓egg cell (ovum)
- •nerve cell
- •red blood cell
- •sperm cell
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