MCQ IN MEDICINE

Detailed explanation-1: -Phytoalexins are toxic antimicrobial substances produced in appreciable amounts in plants only after stimulation by various types of phytopathogenic microorganisms or by chemical and mechanical injury.

Detailed explanation-2: -“Phytoalexins” are the most considered antimicrobial plant defense compounds. These compounds are pathogen specific and therefore more effective in plant defense mechanism. Transcriptional and translational activities in a plant are prerequisite for the production of phytoalexins.

Detailed explanation-3: -Some plants such as mint and witch hazel produce antibacterial chemicals . These limit the spread of bacteria that were not stopped by physical defences. These chemical defences are now used in antiseptics for humans.

Detailed explanation-4: -Defensive chemicals present in plants are broadly classified into nitrogen-and non-nitrogen-containing compounds. Compounds that contain N include cyanogenic glucosides, alkaloids, and nonprotein amino acids. Defensive compounds without N include tannins, terpenes, phytoalexins, steroids, and phenolic acids.

Detailed explanation-5: -Examples of common secondary metabolites used as chemical defenses by plants include alkaloids, phenols, and terpenes. Defensive chemicals used to avoid consumption may be broadly characterized as either toxins or substances reducing the digestive capacity of herbivores.