Question

All cells and many subcellular structures are surrounded by a membrane. Assuming a typical membrane to be about 8 nm wide, how many such membranes would have to be aligned side by side before the structure could be seen with the light microscope? Express your answer as an integer.

Answer 1

The typical light microscope at its maximum magnification power has a resolution of 200 nm. The light microscope is able to view and distinguish between two lines or points that are no less than 200 nm apart. Since our membrane of interest is 8 nm apart, it won't be visible under the light microscope. Several such membranes are needed to lined side by side to make the viewing possible. The number of membranes should be, $\frac{200}{8}$ = 25.