One of the earlier exams in this course asked you to compare two methods of dete

Question

One of the earlier exams in this course asked you to compare two methods of determining bacterial cell concentrations: viable plate counts and direct microscopic counts. I think we can agree,
though, that spectrophotometric measurement of turbidity is a better method than either of those two. Well, maybe not. Describe three significant ways that turbidity measurement is different from both viable plate counts and direct microscopic counts. Which of the three methods is best, and why do you think that? (in 200 words)

Explanation / Answer

Three significant ways that turbidity measurement is different from both viable plate counts and direct microscopic counts are a) The turbidity measurement needs a standard curve to compare the readings. While the other 2 do not. b) In Turbidity measurements the readings are more accurate because, it deals with the calibration of penetration of light through the solution. Whereas, the other 2 involve plating, where the chances of contamination are more. c) The data for a standard solution should be known in case of Turbidity measurement. In absence of such data or even curve, turbidity measurement cannot be quantitative. But the other two are absolute methods and dont have any such pre requisites. I think the Turbidity measurement is best amongst the three. This is because, it is a more accurate technique. In Turbidity measurements the readings are more accurate because, it deals with the calibration of penetration of light through the solution. This is almost a fully automated phenomenon that does not require any human interventio, so the chances of contamination are less.Whereas, the other 2 involve plating, where the chances of contamination are more. In these two first streaking is to be done. Then dilution has to be done and the final step is plating. These procedures increase the chance of contamination, and are carried on manually. So the readings in these cases are not very accurate.

Related Questions

Navigate

• Browse (All)
• Browse O
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.