What are metabolic pathways?

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 enzymes which act as catalysts.

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 substrate
  • finish with an end product
Basic enzyme controlled metabolic pathway. Substrate 1 changed by enzyme 1 becoming substrate 2.  This is changed by enzyme 2 becoming substrate 3 which is changed by enzyme 3 to create end product.

Thousands of metabolic pathways exist and most involve multiple steps – some can be hundreds of steps long! All metabolic pathways together form a complex network that is necessary to maintain life.