Primary and Secondary Metabolites || Primary Metabolites vs Secondary Metabolites

Secondary Metabolites

A plant cell produces two types of metabolites: primary metabolites involved directly in growth and metabolism (carbohydrates, lipids and proteins), and secondary metabolites considered as end products of primary metabolism and not involved in metabolic activity(alkaloids, phenolics, sterols ,steroids, essential oils, lignins and tannins etc).They acts as defense chemicals.Their absence does not cause bad effects in the plants.

Primary and Secondary Metabolites 

Definition:

Secondary metabolites are substances which are produced by plants as defense chemicals. Their absence does not cause bad effects on the plants. They include alkaloids, phenolics, steroids, essential oils,lignins,resins and tannins etc.

Secondary metabolites are compounds biosynthetically derived from primary metabolites. Secondary metabolites, or secondary compounds, are compounds that are not required for normal growth and development and are not made through metabolic pathways common to all plants. In plant kingdom, they are limited to occurrence and may be restricted to a particular taxonomic group (genus, species, or family). Secondary metabolites are accumulated by plant cells in smaller quantities than primary metabolites. These secondary metabolites are synthesized in specialized cells at particular developmental stages, making extraction and purification difficult.

Example of Secondary Metabolites:

Alkaloids	Morphine, Codeine
Essential oils	Lemon grass oil
Drugs	Vinblastin, Curcumin
Lectins	Concanavalin A
Pigments	Carotenoids, Anthocyanins
Polymeric substances	Rubber, Gums, Cellulose
Toxins	Abrin, Ricin
Terpenoides	Monoterpenes, Diterpenes

Primary Metabolites vs Secondary Metabolites

Primary Metabolites	Secondary Metabolites
These are biomolecules required for basic metabolic processes.	These are derivatives of primary metabolites, which are not involved in basic metabolic processes.
These are produced in generous quantities and can easily be extracted from the plant.	These are produced in small quantities, and their extraction from the plant is difficult.
These are found throughout the plant kingdom.	Particular secondary metabolites are found in one plant species or families and not in all plant species.
These are part of the basic molecular structure of the cell.	These are not part of the basic molecular structure of the cell.
They are highly useful to plant.	They have a limited role to play in plants.
They are found from the starting of plant life.	They are found at particular stages of development
Example: Carbohydrates, Proteins, Lipids, Nucleic acid and Vitamins	Example: Alkaloids, Terpenoides