Streaking and Spreading to obtain bacterial colonies

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-The process of growing bacteria started with cleaning your hands and workspace with 70% alcohol.

-The inoculation needle is then sterilised by heating it, and then allowed to cool.

-Now this needle is dipped into the bacteria sample that is antibiotic resistant, and is collected in a petri dish in the form of streaks. The petri dish is rotated at right angles to get four such streaks in one petri dish.

-The needle is once again sterilised using the above mentioned procedure, and is now dipped into the sample that contains bacteria that is not antibiotic resistant.

-The bacteria is once again collected in the petri dish in the same manner as mentioned before. -The petri dishes are marked with labels to distinguish the two and indicate the kind of bacteria it contains.

-These dishes are now placed in an incubator, where the temperature is maintained at 37 degree celsius. ( Which is the optimum temperature for bacteria to grow, as it is the temperature that a human body normally is.)


-The bacteria that is antibiotic resistance is what is found to grow, while the non resistant strain fails to do so.

What is the difference between streaking and spreading?

-Streaking provides us with a gradation of bacterial growth, and allows us to grow single bacteria. Where as spreading involves us using a stirrer instead of the inoculation needle, and the bacteria sample is just spread on the petri-dish.

How is the petri-dish made ready to grow bacteria?

-The petri dish is prepared by mixing agar agar with LB Broth to form LB agar which is the gel that is applied on the petri dish.

Primary metabolites and Secondary metabolites:

-Primary metabolites are the ones that are generated by the bacteria under normal conditions.

-Secondary metabolites are generated when the bacteria is under other circumstance.