Most colonies on streak plates grow from isolated colony-forming units. on rare occasions, however, a colony can be a mixture of two different organisms. if a culture is started from this colony (thinking it's pure), correct identification will be next to impossible because the extra organism could confound the identifying test results. how could you verify the purity of a colony? if you found the colony to be a mixture of organisms, what could you do to purify it?

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Biology

Luke Anderson

16 June, 13:04

Most colonies on streak plates grow from isolated colony-forming units. on rare occasions, however, a colony can be a mixture of two different organisms. if a culture is started from this colony (thinking it's pure), correct identification will be next to impossible because the extra organism could confound the identifying test results. how could you verify the purity of a colony? if you found the colony to be a mixture of organisms, what could you do to purify it?

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Jase Davenport · Answer 1

To verify the purity of a colony, a number of steps could be adopted. Pick the colony and dissolve it in sterile water (approximately 5ml), streak in media again and incubate. Observe if it produces pure colonies of the chosen organisms and if not, repeat the procedure until pure colonies are produced. Additionally, one could perform additional tests that categorize bacteria such as Gram staining.