Metabolism refers to all of the chemical reactions that take place inside living cells. Unicellular and multicellular organisms must control their metabolism in order to survive.
All cells produce substances that are essential for them to function properly.
Metabolic pathways are integrated and controlled reactions within a cell. These reactions are controlled by the presence or absence of enzymeA protein which catalyses or speeds up a chemical reaction. which act as catalyst A substance that increases the rate of a chemical reaction without being used up..
In animals, specific metabolic pathways can produce vitamins and haemoglobin.
Metabolic pathways can be described as a series of chemical reactions that:
start with a substrateA substance on which enzymes act.
finish with an end product
Thousands of metabolic pathways exist and most involve multiple steps 鈥 some can be hundreds of steps long! All metabolic pathways together form a complex network that is necessary to maintain life.