NUTRITION
Carbohydrates, fats, proteins and vitamins are organic substances because they contain carbon in their molecular structure. Water and minerals are inorganic substances since they don’t contain carbon. Carbohydrates, fats and proteins are needed in bulk in our diet, while vitamins and minerals are needed in smaller amounts.
A person whose diet lacks any of these nutrients suffers from malnutrition, and this may give rise to a deficiency disease. Food gives us energy. The amount of energy needed by our body isn’t the same for everyone. The amount of energy needed to live depends on the person’s sex, job, attitude, age and other factors like if the person is a pregnant woman.
Carbohydrates are organic substances made up of carbon, hydrogen and oxygen. They are very important because they provide energy for the body. There are 3 types of carbohydrates: sugars, starch, and cellulose.
Carbohydrates are all made up of molecules of glucose bonded (joined) together. The simplest form of carbohydrate is glucose. Two molecules of glucose joined together with a bond, form maltose, lactose and sucrose sugars. Starch, cellulose and glycogen are formed when 3 or more glucose molecules are joined together with bonds.
A single sugar molecule is called a monosaccharide. Examples of monosaccharides
are glucose and fructose.
Sucrose, maltose and lactose are all disaccharides because they have 2 sugar
molecules bonded together.
Starch, cellulose and glycogen are all polysaccharides because they are made up of
3 or more sugar molecules bonded together.
2. Proteins
Proteins are organic substances made up of hydrogen, carbon and oxygen, nitrogen and sometimes they contain sulphur. Proteins are needed by the body to grow and repair tissues (a cellular structure), they are components of cell membranes, are used to produce enzymes (biological catalysts) and hormones. The simplest possible protein is an amino acid, thus proteins are made up of amino acids, which can be represented as any form of shape (circle, rectangle, square).
3. Fat
Fats are organic substances. Lipids are fats in a liquid state. Fats are useful for our body, because they
· provide energy,
· can be stored for later use,
· build up cell membranes,
· layers serve as an insulating layers under mammal’s skins and
· and oils on the surface of the skin makes the skin waterproof.
Fat is found in vegetable oil, milk, fried foods, eggs, beef etc. The simplest fat molecule is made up of 1 molecule of glycerol and 3 fatty acids bonded together.
