what would happen if you did not use a new sterile loop between streak 1 and streak 2 of the plate
The correct answer and explanation is:
If a new sterile loop is not used between streak 1 and streak 2 during a streak plate method, the primary consequence is that the bacterial sample from streak 1 would contaminate the streak 2 area. This results in the inability to isolate pure colonies of a single bacterial species.
The streak plate method is designed to spread bacterial cells over the surface of an agar plate in a way that eventually leads to the formation of distinct colonies. Each colony should arise from a single bacterium, ensuring it is a pure culture. When a sterile loop is not used between streak 1 and streak 2, the bacteria from streak 1 are carried over into streak 2. This will lead to a mixed population of bacteria in the second section of the plate, preventing the isolation of individual colonies in the subsequent streaks. As a result, colony count and identification can be inaccurate because overlapping growth occurs, making it difficult to differentiate between the various types of bacteria.
Additionally, if the streaking procedure is done improperly by transferring bacteria from one streak to another, the dilution gradient that should occur across the plate is disrupted. This prevents the separation of bacterial cells, and as a result, no distinct, isolated colonies will form. The growth from streak 2 will be denser and could overlap with growth from streak 1. Therefore, for successful isolation and identification of a single bacterial species, maintaining sterility between each streak is crucial.