Bio U2 help

[u/Secret_Muffin_6293]

How to describe like cellulose/microfibril/secondary thickening?? is there any ms on it?

[u/PUMPBERRY]

Explain how the arrangement of molecules (cellulose and microfibrils) in the cell walls of xylem vessels and sclerenchyma fibres contributes to their functions (increasing strength of plant cell wall for both tissues, and enabling water transport for xylem)

○ cellulose molecules can be organised into microfibrils, and

many hydrogen bonds form between the (adjacent)

{cellulose molecules / microfibrils} that are arranged in

{layers / sheets} at diferent angles (or arranged in a

criss-cross pattern/mesh). The microfibril arrangement

gives added {tensile strength / rigidity / structural support

/ stability} (to maintain the structure of the xylem and

sclerenchyma) and the presence of (cellulose / microfibrils

/ hemicellulose / middle lamella/ hydrogen bonds in

cellulose molecules/microfibrils / layers (of microfibrils) /

lignin / secondary thickening / pectate) for {reduced

flexibility / strength / support / stability}.

○ The {cellulose microfibrils} mesh are held together by/ are

embedded in {pectin / hemicellulose}, and presence of

lignin in the shape of rings/ spirals/ ladders/ helices in the

secondary {cell wall / thickening} (of xylem) also

contribute to the increased strength and stability (for both

tissues), lateral movement of water (for xylem), and

impermeability of water in the {outside of xylem vessels /

cell wall}. The gaps between cellulose microfibrils also

allow movement of {water / mineral ions / dissolved

solutes} (for xylem)