KS3 Science · Biology
Food and digestion
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Key words
Balanced diet Eating the right amount of each nutrient, with fibre and water
Carbohydrate The body’s main source of energy: starch and sugars
Lipid A fat or an oil, which the body can store for energy
Protein The nutrient used to build new tissue for growth and repair
Vitamins Needed in small amounts, and named with letters such as A, C and D
Minerals Needed in small amounts: iron and calcium are two of them
Dietary fibre Parts of plants that cannot be digested
Kilojoule The unit of energy on a food label
Deficiency disease An illness caused by too little of one vitamin or mineral
Starvation Taking in far too little energy for a long time
Obesity Having so much stored body fat that it can harm health
Digestion Breaking large food molecules into small ones
Enzyme A substance that speeds up the chemical reactions of digestion
Stomach A bag where food is mixed with acidic juices
Small intestine Where digestion is completed and food is absorbed into the blood
Large intestine Where water is absorbed and faeces are formed
Villi Tiny finger-shaped bumps that line the small intestine
Gut bacteria Microorganisms that live in the intestine and help to break down food