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

Carbohydrates

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

Also See:

PROCESS OF PHOTOSYNTHESIS

NUTRITION IN PLANTS

BIOLOGY PRACTICAL

ACTIVE TRANSPORTWATER RELATIONS IN PLANT AND ANIMAL CELLS