Bacteria are among the smallest living things. A single bacterium consists of just one cell, and is called a single-celled, or unicellular organism. There are millions of different types of bacteria.

This protects the bacteria from drying out and physical stress. In addition, the capsule makes the pathogens invisible to our body's own defenses, so to speak, and helps them to survive in the body.

and he observed that these bacteria had the smooth capsules characteristic of the S strain. Based on these observations, Griffith hypothesized that a chemical component from the virulent S cells ...