Diatoms are golden brown algae, belongs to class-Bacillariophyceae. Cell wall of diatoms is made up of silica. The diatoms after death get deposited at bottom of the water reservoirs. These deposites of diatoms are called diatomaceous earth. Diatomaceous earth is used as insulator in boiler and blast furnace.
Cell membrane is the outer most part of cytoplasm is made up of lipid protein and carbohydrates.
Protoplasm is a clear, colourless jelly like gelatinous substances. It include two part cytoplasm and nucleus.