NEET BIOLOGY

Detailed explanation-1: -A frustule is the hard and porous cell wall or external layer of diatoms. The frustule is composed almost purely of silica, made from silicic acid, and is coated with a layer of organic substance, which was referred to in the early literature on diatoms as pectin, a fiber most commonly found in cell walls of plants.

Detailed explanation-2: -Plants take up silicic acid from water. Silicon in higher plants is incorporated into cell walls, making stems and leaves more rigid and strong. Among the phyto-plankton, diatoms have a particular need for silicon, because their frustules – the hard but porous cell walls – are composed almost entirely of silica.

Detailed explanation-3: -Diatoms can vary greatly in both size and form, but they all have a characteristic outer cell wall (or frustule) made of biogenic silica.