Final answer:
First generation cephalosporins have a narrow spectrum of coverage mainly against gram-positive bacteria. They inhibit cell wall synthesis and are less effective against resistant strains that produce ß-lactamases.
Step-by-step explanation:
The first generation cephalosporins have a narrow spectrum of coverage, primarily targeting gram-positive bacteria and limited numbers of gram-negative bacteria.
They also show activity against Mycobacterium tuberculosis. These antibiotics, similar to penicillins, inhibit cell wall synthesis in bacteria, leading to their death.
However, they are less effective against resistant strains that produce ß-lactamases, enzymes that can inactivate the antibiotics.