Final answer:
The size of the zone of inhibition in the disk diffusion test depends on the sensitivity of the bacteria to the specific antimicrobial agent and the point at which the chemical's saturation concentration is reached. Larger zones indicate increased inhibition effectiveness of the chemical agent.
Step-by-step explanation:
The size of the zone of inhibition in the disk diffusion test depends on the sensitivity of the bacteria to the specific antimicrobial agent and the point at which the chemical's saturation concentration is reached. The disk-diffusion method involves applying different chemicals to separate, sterile filter paper disks. The disks are then placed on an agar plate that has been inoculated with the targeted bacterium, and the chemicals diffuse out of the disks into the agar where the bacteria have been inoculated. Larger zones typically correlate to increased inhibition effectiveness of the chemical agent, as observed as clear areas around the disks.