Microbiology - Bacteria Morphology - Discussion

The periplasm is a concentrated gel-like matrix in the space between the inner cytoplasmic membrane and the bacterial outer membrane called the periplasmic space in gram-negative bacteria. It has been found using cryo-electron microscopy, that a much smaller periplasmic space is present in gram-positive bacteria.

The periplasm may constitute up to 40% of the total cell volume of gram-negative bacteria, and this is a much smaller percentage in gram-positive bacteria.

So option A &B Both correct then how we can choose option A?

A & B both correct because they have layers inner and outer.

There is no outer membrane in gram-positive bacteria.

Both gram negative and positive bacteria have periplasmic space; gram negative has higher volume.