Sclerenchyma secondary cell walls are impregnated with_________________?
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Answer: C. Lignin.
Explanation
Sclerenchyma cells develop thick secondary cell walls that are heavily impregnated with lignin for rigidity. Lignin cross-links with cellulose microfibrils to create a rigid, waterproof composite cellular structure. This chemical impregnation provides immense mechanical support allowing plants to grow upright against gravity. Sclerenchyma tissue consists of dead supportive plant cells with thick, lignified secondary cell walls. Fibers and sclereids are the two main morphological types of sclerenchyma cells found in plant organs. Cellulose is the primary structural carbohydrate polymer making up the foundational plant primary cell wall.
Commercial hemp and flax fibers utilize tough sclerenchyma cells to produce durable textiles and ropes. Lignified cell walls give pear flesh its characteristic gritty texture due to clustered stone cells. Plant pathologists study sclerenchyma reinforcement as a natural defense barrier against herbivore grazing. Cellulose forms the basic framework of plant cell walls, but secondary rigidification requires lignin impregnation. Peptidoglycan and murein are structural components found in bacterial cell walls rather than plant sclerenchyma. Pectin is a gelatinous polysaccharide found in middle lamellae that cements adjacent plant cells together.
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