Final answer:
Individuals grown in a liquid culture can be counted when transferred to an agar plate, with each growth forming a visible colony representing descendants of a single bacterial cell. Methods such as streak plate, spread plate, and pour plate are used for counting and isolating bacteria.
Step-by-step explanation:
Individuals grown in a liquid culture can be counted when transferred to an agar plate. Each gives rise to a visible colony. This process can be executed using methods such as the streak plate, spread plate, or pour plate method. In these techniques, a single type of bacterium is isolated, and single cells reproduce to create millions of clones, all piling up to form what is called a colony. Consequently, each colony represents the descendants of a single bacterial cell, allowing scientists to achieve a pure culture of the bacterium.
Furthermore, techniques like the viable plate count are used to count viable or live cells based on the principle that these cells will replicate and form visible colonies on an agar plate under suitable conditions. This count is generally expressed as colony-forming units per milliliter (CFU/mL). Different bacteria can give rise to colonies with distinct characteristics such as size, color, shape, and form, known as colonial morphology, which can aid in the preliminary identification of the bacterial species.