Question

Is bacteria an antigen? If not, what is the difference between bacteria and an antigen?

Answer 1

No

Explanation:

Bacteria is simply a prokaryote ( Kingdom Monera ).

Antigens are usually proteins or polysaccharides which are present on the surface of cells of bacteria etc.
Or we can also define antigen as any substance that causes an immune system to produce antibodies against it.

When any foreign antigen comes inside our body , the immune system recognises it as foreign body and produce antibodies against it.