A covalent bond, also called a molecular bond, is a chemical bond that involves the sharing of electron pairs between atoms.
The difference between them is that they are active in fighting infection.
Plasma cells are active in defense during the first exposure to invaders like viruses or bacteria producing antibodies. Memory cells last longer and make a copy of the invaders. This allows an extremely rapid defense later in case of a second exposure.
B. synaptic space
and after into the a. cell membrane
