Question

What are secondary metabolites? Name five secondary metabolites and their role in plant life.

Answer 1

A metabolite is a metabolic intermediary or end product formed during biological reactions occurring in living systems. Small molecules are typically referred to as metabolites. Fuel, structure, signaling, stimulatory and inhibitory effects on enzymes, catalytic activity (typically as a cofactor to an enzyme), defense, and interactions with other species (e.g. pigments, odorants) are all functions of metabolites.

Complete answer:
All biochemicals produced during metabolism that aren't directly engaged in the growth and development of the plant are classified as secondary metabolites. These metabolites can play a variety of functions in the plant defence system, signalling processes, and interactions with various microbial species, but they are not required for the species' survival.
A few examples of secondary metabolites and their role in plant life are as follows:
1. Terpenoids: It's also known as isoprenoids, and it's one of the most common types of secondary metabolites. These compounds are poisonous to insects and animals that eat them, and hence play a function in the defense system. Pyrethroids (Monoterpene esters) are insecticidal compounds found in the leaves and flowers of Chrysanthemum spp.
2. Alkaloids: Amino acids like lysine, tyrosine, and tryptophan are used to make alkaloids. Nitrogen-containing substances include morphine, caffeine, and cocaine. Alkaloids include substances like coniine and nicotine. They have a harsh taste and defend plants from animals.
3. Latex: Latex is a milky fluid present in ten percent of all blooming plants in nature (angiosperms). Proteins, alkaloids, starches, sugars, oils, tannins, resins, and gums form a complex emulsion that coagulates when exposed to air. It is generally released as a result of tissue damage.
4. Phenolics: Flavonoids, polyphenols, and other phenolics are secondary metabolites with phenol groups in their structure. More than $8000$ different phenolics are discovered in the plant. These molecules have different roles such as signalling, protection, the attraction of pollinators, pigmentation, absorption of UV rays, reducing the growth of the competitive plant species.
5. Salicylic acid: The activation of the plant defense system is also aided by salicylic acid. The plant defense system is activated by hormonal interaction between Cytokines and SA. Plant growth, transpiration, ion absorption, photosynthesis, and transpiration are all functions of salicylic acid.

Note:
Secondary metabolites are utilized in a variety of products, including medicines, flavors, perfumes, insecticides, and dyes, and have a high economic value. These new methods will help to extend and improve the utilization of higher plants as chemical rejuvenation sources, particularly therapeutic substances. For example Quinoline derivatives are used as antimalarial drugs.