Chemical Compounds which Constitute Living Organisms

All matter is made up of chemical elements, each of which exists in the form of smaller units called atoms

1. Some of the elements occur in large amounts in living things
2. These include carbon, oxygen, hydrogen, nitrogen, sulphur and phosphorus
3. Elements combine together to form compounds
4. Some of these compounds are organic
5. Organic compounds contain atoms of carbon combined with hydrogen and they are usually complex
6. Other compounds are inorganic
7. Most inorganic compounds do not contain carbon and hydrogen and they are usually less complex
8. Cells contain hundreds of different classes of organic compounds
9. However, there are four classes of organic compounds found in all cells
10. These are: carbohydrates, lipids, proteins and nucleic acids

Carbohydrates

1. Carbohydrates are compounds of carbon, hydrogen and oxygen
2. Hydrogen and oxygen occur in the ratio of 2: 1 as in water
3. Carbohydrates are classified into three main groups: monosaccharides, disaccharides and polysaccharides