What conclusion can you draw from the graph?
a) The wire loop is already carrying bacteria from the chicken farm sample
b) The agar plate is not sterile
c) We haven’t collected any bacteria yet so the wire loop is sterile
d) The wire loop is not sterile
The correct answer and explanation is :
In microbiology labs, sterile technique is crucial when transferring bacteria from a sample to an agar plate, and this often involves using a wire loop. A graph related to this context could display bacterial growth on an agar plate over time or show contamination levels based on various conditions, such as the presence of bacteria from the wire loop.
Let’s break down each option:
a) The wire loop is already carrying bacteria from the chicken farm sample
If the graph shows bacterial growth on the agar plate from the initial streak (before any collection of a sample), it could suggest that the wire loop already had bacteria on it. This would imply that the wire loop was not sterilized properly, and bacteria from the chicken farm sample were transferred to the agar plate. However, if there is no bacterial growth until after collecting the sample, this conclusion is less likely.
b) The agar plate is not sterile
If the graph shows bacterial growth from the start, before any samples were collected, it could indicate contamination of the agar plate. This could happen if the plate was not properly prepared or handled before inoculation. However, if the bacterial growth is confined to the streaks made with the wire loop, this is unlikely.
c) We haven’t collected any bacteria yet so the wire loop is sterile
If there’s no bacterial growth after streaking the plate with the wire loop (and before collecting the sample), it might suggest that the wire loop was sterile. However, this would depend on how the experiment is conducted (e.g., the conditions of sterilization, time of exposure).
d) The wire loop is not sterile
If the graph shows bacterial growth before any sample collection, it could suggest that the wire loop was contaminated, which means it wasn’t sterile. This is a reasonable conclusion if the graph indicates growth from the wire loop alone, even without the chicken farm sample being introduced.
Conclusion:
The most likely correct answer, based on typical interpretations of bacterial culture graphs, would be d) The wire loop is not sterile. This is because if the graph shows bacterial growth from the wire loop without any other sample being collected, it suggests contamination from the wire loop itself. This conclusion assumes that the wire loop was not properly sterilized before use, allowing bacteria to transfer to the agar plate.