Nutrition, digestion and excretion

The seven nutrients are carbohydrates, proteins, lipids(fats and oils), minerals, vitamins, fibre, water
Each person needs a different amount of energy depending on factors such as: gender (male or female), age, amount of daily activity
A one-year-old baby needs 3850 kJ each day to continue to grow, whereas an adult Olympic swimmer in training needs 15,600 kJ each day
Too little food=underweight too much food=overweight
The average man needs about 10,470 kJ per day, and the average woman needs about 8370 kJ per day.
KJ is the meauserment for food energy
.An poor diet can contain too much or too little of a particular nutrient. Too little of a nutrient, you have a deficiency. For example, fibre keeps food moving through the intestines, people who have a fibre deficiency may get constipation.
vitamin A deficiency can cause blindness, vitamin C deficiency causes scurvy, which makes the gums bleed and vitamin D deficiency causes rickets, which makes the legs bow outwards in growing children
The food we eat has to be broken down into other substances that our bodies can use. This is called digestion. Without digestion, we could not absorb food into our bodies and use it.
After we swallow, our food passes through these organs in turn: oesophagus or gullet, stomach, small intestine, large intestine
Enzymes are not living things. They are special proteins that can break large molecules into small molecules. Different enzymes break down different things: amylase and other carbohydrase enzymes break down starch into sugar, protease enzymes break down proteins into amino acids, lipase enzymes break down lipids (fats and oils) into fatty acids and glycerol
Absorption across a surface happens quickly and efficiently if: the surface is thin its area is large The inner wall of the small intestine has adaptation so that substances pass across it quickly and efficiently:-it has a thin wall, just one cell thick it has many tiny villi to give a really big surface area
Waste is passed on and excreted

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Nutrition, digestion and excretion

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