Question

If you calculated your cell concentrations using plate count method, a spectrophotometer, and a petroff-hausser cell counter, how would the values be different?

a. Petroff-Hauser counting chamber would have a lower reading than the plate count method.
b. The value obtained using a spectrophotometer would have a lower reading than the plate count method.
c. The Petroff-Hauser counting chamber would have a far higher value than the spectrophotometer value.
d. The plate count value would be the lowest value of the three methods.

Answer 1

The Petroff-Hauser counting chamber is expected to show a significantly higher value compared to the spectrophotometer, emphasizing the importance of choosing appropriate methods based on the research objectives and the characteristics of the cell population. (option c is the correct answer)

Step-by-step explanation:

The differences in cell concentration values obtained using different methods stem from the principles and limitations of each technique. The Petroff-Hauser counting chamber involves direct microscopic counting of cells, providing a more accurate and specific count compared to indirect methods.

In contrast, a spectrophotometer measures the turbidity of a solution, which might not distinguish between live and dead cells or different cell sizes, leading to a potentially lower reading.

The plate count method involves culturing viable cells on a solid medium, and its values may be lower than direct counting due to factors such as the inability to culture all types of cells.

The Petroff-Hauser counting chamber is likely to yield a higher value than the spectrophotometer, as it provides a direct count of viable cells, capturing a more comprehensive picture of cell concentration.