Difference Between Primary and Secondary Metabolites

Primary vs Secondary Metabolites

Metabolites are involved in the growth of organisms through the process of metabolism. The metabolism is referred to as the sum of the all the biochemical reactions carried out by an organism. Depending on the origin and function, metabolites can be divided into two major categories; namely, Primary and Secondary metabolites.

Primary Metabolites

Primary metabolites are essential to the growth of the cell. They are produced continuously during the growth phase and are involved in primary metabolic processes such as respiration and photosynthesis. Primary metabolites, which are identical in most organisms, include sugars, amino acids, tricarboxylic acids, the universal building blocks, and energy sources. Other than the above compounds, proteins, nucleic acids, and polysaccharides are also considered as primary metabolites.

Secondary Metabolites

Secondary metabolites are the compounds which are derived by pathways from primary metabolic routs, and are not essential to sustain the life of cells. These compounds do not have a continuous production. Very often secondary metabolites are produced during non- growth phase of cells. Secondary metabolites are the end products of primary metabolites such as alkaloids, phenolics, steroids, essential oils, lignins, resins and tannins etc.

What is the differences between Primary Metabolites and Secondary Metabolites?

• Unlike secondary metabolites, Primary metabolites are essential to cell growth, and they are involved directly in metabolic reactions such as respiration and photosynthesis.

• Most primary metabolites are identical among most organisms, whereas secondary metabolites are numerous and wide spread, unlike the primary metabolites.

• Secondary metabolites are derived by pathways in which primary metabolites involve. Therefore, secondary metabolites are considered as the end products of primary metabolites.

• Primary metabolites are produced during the growth phase of cell while secondary metabolites are produced during the non- growth phase of the cell.

• Secondary metabolites are accumulated by plant cells in very small quantities than primary metabolites.

• The growth phase where primary metabolites are produced is sometimes called ‘trophophase’, whereas the phase during which secondary metabolites are made is called ‘idiophase’.

• Most of the secondary metabolites are involved in defense reactions, unlike the primary metabolites.

• Proteins, carbohydrates, and lipids are the main primary metabolites, whereas secondary metabolites are alkaloids, phenolics, sterols, steroids, essential oils and lignins etc.