Q. Which of the following statement of a bacterial cell is/are correct?
(i) Mesosome is formed by the extensions of plasma membrane into the cell.
(ii) The pili are elongated tubular structures made up of a protein.
(iii) Flagellum is composed of filament, hook and basal body.
(iv) Ribosomes are about by in size.

 579  159 Cell : The Unit of Life Report Error

Solution:

Ribosomes are about 15 nm by 20 nm in size.