MODEL PAPER 8 — BIOLOGY STD 11 Science — Question

It is true that the cells of unicellular organisms tend to be spherical. It is because of the following reasons:
i. Surface tension: Surface tension shapes the spherical way as in the case in air-borne soap bubbles.
ii. The free-floating cells with thin membranes tend to be spherical as it is the most economical shape that can confine a given mass of protoplasm. The shape and the size of the cell depend upon the place where they are present and the functions they have to perform. In multicellular animals, the cells tend to become faceted as they come in contact with each other in the same way as the spherical soap bubbles become flattened when they are jammed together in a small space.