2. Metals are essential for the proper functioning of living organisms. Some metal elements act as coenzymes and cofactors. These elements are called trace metals. Without trace metals certain enzymes would not work.

3.  Magnesium functions as part of the structure of chlorophyll. Chlorophyll is the green pigment that carries out photosynthesis. MAGNESIUM IN CHLOROPHYLL

4.  Iron forms part of the structure of haemoglobin which is the pigment in red blood cells that transports oxygen around the body. Iron is also essential for the absorption of sunlight for energy. IRON IN HAEMOGLOBIN

5.  Some metals are toxic to living organisms. The toxic metals are particularly ‘heavy’ metals. E.g. transition metals POLLUTION BY METALS AND THEIR COMPOUNDS

6.   Mercury - from fossil fuel burning - dental fillings - canned tuna - manufacture of cement - fertilizers - compounds in the industry which causes nervous disorders or even death. Some toxic metals are:-

7.   Lead - from lead headed nails - lead fuel from vehicle paints - car exhausts which affects enzymes, impairing cell metabolism. It can cause brain damage and even death. Some toxic metals are:-

8.   Copper - from water pipes and heaters - copper jewellery/ copper pots - meat in which CuSO 4 is used as an enhancer. Some toxic metals are:-

9.  Many non-metals elements are continually being reused and recycled by nature and passed through the bodies of living organisms to be used by other organisms. NON-METALS

10.   Ensures a constant supply of water is available to plants for photosynthesis.  Ensures water is available to all living things to keep their cells hydrated and to act as a solvent.  Ensures aquatic organisms a place to live. IMPORTANCE OF THE WATER CYCLE

11.  THE WATER CYCLE

12.   Maintains a constant level of CO 2 in the air and that a constant supply of carbon is available to plants for photosynthesis.  Ensures a constant supply of organic food is available to animals and decomposers. IMPORTANCE OF THE CARBON CYCLE

13.  THE CARBON CYCLE

14.   Maintains a constant concentration of nitrogen in the air.  Ensures a continuous supply of nitrates protein synthesis.  Ensures a continuous supply of protein to animals and decomposers. IMPORTANCE OF THE NITROGEN CYCLE

15.  THE NITROGEN CYCLE

16.  1.Carbon dioxide is essential for photosynthesis. 6CO 2(g) + 6H 2 O (l) → C 6 H 12 O 6(aq) + 6O 2(g) 2.Oxygen is essential for aerobic respiration. C 6 H 12 O 6(aq) + 6O 2(g) → 6CO 2(g) + 6H 2 O (l) + energy 3.Nitrates and sulphates are essential for protein synthesis in plants. IMPORTANCE OF NON-METALS

17.  4.Phosphorus, obtained as PO 4 3- ion is essential for building small bones and teeth. 5.Water is essential as: -a solvent to dissolve body chemicals and enzymes so they can react. -for hydrolysis occurring during digestion. -as a reactant in photosynthesis. -as a coolant when it evaporates. IMPORTANCE OF NON-METALS

18.  Pollution is the contamination of any feature of the environment by unpleasant or harmful substances within the environment. POLLUTION BY COMPOUNDS OF NON-METALS

19.  Sulphur dioxide – combines with water vapour and smoke forming smog which causes respiratory diseases and even death. It also dissolves in rain water forming acid rain which is harmful to plants and animals and corrodes metal structures and buildings. SOME HARMFUL POLLUTANTS

20.  Hydrogen sulphide – extremely toxic and causes respiratory disease. Carbon monoxide – combines with haemoglobin forming carboxyhaemoglobin which prevents blood carrying oxygen and results in headaches, unconsciousness and death. SOME HARMFUL POLLUTANTS

21.  Carbon dioxide – the build up of heat causes atmospheric temperatures to rise resulting in ice caps and extensive flooding. Insecticides – remain in environment and concentrate up food chains harming and killing top consumers. SOME HARMFUL POLLUTANTS