What's covered
Key facts
A balanced diet provides all the essential nutrients in the right amounts and proportions for the body to function healthily.
Alcohol slows reaction times, impairs judgment, damages the liver (cirrhosis) with long-term use, and increases the risk of accidents and addiction.
Aerobic exercise (e.g. running, swimming) uses oxygen and can be sustained for long periods; it improves cardiovascular fitness.
Alveoli are adapted for efficient gas exchange by having a large surface area, very thin (one-cell-thick) walls, and a rich blood supply.
Amylase is the enzyme that breaks down starch (a carbohydrate) into smaller sugars such as glucose.
The female sex cell (gamete) in humans is the egg cell, also called the ovum, produced in the ovaries.
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.
Carbohydrates (sugars and starch) are the body's primary energy source; they are broken down to glucose which is used in respiration.
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.
Anaerobic exercise (e.g. sprinting, weightlifting) occurs when oxygen demand exceeds supply; it produces lactic acid and can only be sustained briefly.
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 is protein mainly needed for in the body?
- ✓Growth and repair of body tissues
- •Helping food move through the digestive system
- •Insulating the body and storing energy
- •Providing the body's main store of energy
What are the seven food groups?
- •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
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