Question

Explain the different types of secondary metabolites, listing the major chemical group types and some examples of their roles

Explain, using examples, why secondary compounds are important to plant long-term survival even if they are not involved in primary metabolic processes.

Discuss, using detailed examples, whether plants are really ‘helpless sessile organisms’... or not?

Explain the detailed steps and components of the process of plant responses to a viral, bacterial or fungal pathogen involving the hypersensitive response and that leads to SAR

Answer 1

secondary metabolites are organic compounds produced by bacteria, fungi or plants ,which are not directly involved in the normal growth ,development or reproduction of the organisms

secondary metabolites	chemical group(phenolic)	examples of their role
anthocyanin	flavonoids	leaf and flower pigmentation,
gallotannin	tannins	bind to protein,enzyme
lignin	lignin	structure,toughness,fiber

many secondary compounds are important to plant long-term survival.they will protect plants from herbivory and microbial infection, as attractants for pollinators and seed dispersing animals and as allelopathic agents.for eg; alkaloids ;which discourage predators with noxious odors and repellent taste.caffeine is an example of alkaloid which affect herbivores by causing excessive stimulation.in this way they can help for long term survival.

plants are not' helpless sessile organism'.eventhough plants are sessile organisms(permanently restricted to their site of germination) they are not helpless.to compensate their sessile nature ,they evolved unique mechanisms enabling them to rapidly react and adjust to their environment.they can defense against biotic and abiotic stress.so they are not helpless.for eg; cacti adapted for the desert environment.they have thin leaves in the form of thorns all over its stem and also the stem is very thick to store water.water is scare in the desert ,the plant soaks up and stres whatever water it can when it rains and then uses its water reserve when there is no water.