1. (Biochemistry) the sum total of the chemical processes that occur in living organisms, resulting in growth, production of energy, elimination of waste material, etc. 2. (Biochemistry) the sum total of the chemical processes affecting a particular substance in the body: carbohydrate metabolism; iodine metabolism.
It is found only in cultivation, where it is the most commonly grown of all plants in the Nicotiana genus, and its leaves are commercially grown in many countries to be processed into tobacco.It grows to heights between 1 to 2 metres.he concentration of nicotine increases with the age of the plant. Tobacco leaves contain 2 to 8% nicotine combined as malate or citrate. The distribution of the nicotine in the mature plant is widely variable: 64% of the total nicotine exists in the leaves, 18% in the stem, 13% in the root, and 5% in the flowers.
1 Cadmium: This metal is found most often in batteries and is the main ingredient in battery acid. 2  Smokers typically have twice as much cadmium in their bodies as non-smokers do. 3  Arsenic: This metal substance is most often used as a pesticide or fertilizer.here are many different poisonous substances found in tobacco. Some of these are found in products such as rat poison and pesticides, while others are found in household cleaners and solvents.