Metabolism –
the sum of all the controlled chemical reactions/chemical pathways occurring in cells. These metabolic pathways allow the organism to grow and reproduce, maintain their structures and respond to environmental changes. In chemical pathways, one chemical is transformed into another by a sequence of enzyme regulated reactions.
Enzymes
help to maintain the ideal conditions for cells in the body, called homeostasis.There are two types of metabolic pathways:
- 1. Anabolism – is a constructive metabolic process Cell creates complex molecules from simpler molecules, this requires energy
Anabolism involves three stages:
- 1. the production of precursors such as amino acids, monosaccharides, isoprenoids and nucleotides
- 2. their activation into reactive forms
- 3. the assembly of these precursors into complex molecules
Examples:
amino acid + amino acid -> protein
glycerol + fatty acids -> triglycerides
glucose + glucose -> glycogen
- 2. Catabolism – is a deconstructive metabolic process
Catabolism is breaking down organic matter which releases energy and therefore is exothermic.
The purpose of catabolic reactions is to provide the energy and components needed by anabolic reactions.
Examples
Protein -> amino acids + energy
Triglycerides -> fatty acids + glycerol + energy
glycogen -> glucose + energy