(ii) Plant fibres consisting of sclerenchyma and xylem tissues contain cellulose in their cell walls. Explain how tensile strength is related to the arrangement of cellulose in plant fibres.
Answer (2)
Tensile strength in plant fibers is derived from the structural arrangement of cellulose, which forms strong, parallel chains and bundles known as microfibrils. This arrangement, along with the presence of lignin and other compounds, enhances the ability of the fibers to resist stretching and breaking. Therefore, the overall organization and composition of cellulose in plant tissues are crucial for their strength.
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Cellulose is a primary structural component in the cell walls of plant fibers, like sclerenchyma and xylem tissues. Its arrangement significantly contributes to the tensile strength of these fibers, which is crucial for the plant's structural integrity.
Cellulose Structure : Cellulose is a carbohydrate composed of long chains of glucose molecules. These chains are aligned in a linear fashion and form bundles known as microfibrils. These microfibrils are extremely strong due to the numerous hydrogen bonds that form between the hydroxyl groups of adjacent cellulose molecules.
Arrangement of Cellulose : In plant fibers, the cellulose microfibrils are aligned parallel to each other and are embedded within a matrix of other polysaccharides and proteins. This arrangement resembles a composite material where cellulose fibers act like reinforcement rods, giving the plant rigidity and strength.
Tensile Strength : The parallel arrangement and tight packing of cellulose microfibrils contribute to the tensile strength by allowing fibers to resist pulling forces. The hydrogen bonds between cellulose fibers provide additional strength and flexibility, preventing the fibers from tearing easily under tension.
Therefore, the structural arrangement and chemical composition of cellulose within plant fibers play a crucial role in enhancing their tensile strength, enabling the plant to withstand various mechanical stresses.
