AP BIOLOGY

Detailed explanation-1: -Sclerenchyma tissue, when mature, is composed of dead cells that have heavily thickened walls containing lignin and a high cellulose content (60%–80%), and serves the function of providing structural support in plants.

Detailed explanation-2: -Lignin is one of the main components of plant cell wall and it is a natural phenolic polymer with high molecular weight, complex composition and structure.

Detailed explanation-3: -Lignin is a component of the cell walls of sclerenchymatous cells. Two types of sclerenchyma cells exist-fibres and sclereids. Their walls consist of cellulose, hemicellulose, and lignin. Sclerenchyma cells are the dead cells in plant tissues that play a vital role in providing mechanical support to the plants.

Detailed explanation-4: -Lignin is an organic substance belonging to a group of aromatic alcohols. It is naturally produced by certain plants (especially woody plants and certain algal species). It is found in the secondary cell walls of plants where it serves as a binder for cellulose fibers and provides stiffness to the cell walls.

Detailed explanation-5: -Lignin (Latin lignum ‘wood’) is a polyphenolic polymer deposited directly in the cell wall of specialized cells. It is not only restricted to plant woody tissues but represents an integral feature ensuring the proper cellular function of many other cell types in different tissues/organs of the plant.