Microbial cell colonies can be grown on a solid growth medium or within a liquid growth medium. If you wanted to count the number of bacteria cells in a small colony found in a liquid broth, which counting technique would you use?

• A. Flow cytometry.
• B. Coulter counting.
• C. Membrane filtration.
• D. Direct microscopic cell counting.
• E. None of the above.

Answer: (C)

Verified step by step guidance

1. Understand the context: You need to count bacteria cells in a liquid broth. This requires a method that can handle liquid samples effectively.
2. Consider the options: Flow cytometry, Coulter counting, membrane filtration, direct microscopic cell counting, and none of the above.
3. Flow cytometry: This technique uses laser technology to count and analyze the physical and chemical characteristics of cells. It is suitable for liquid samples but may not be the most practical for small colonies.
4. Coulter counting: This method counts cells by detecting changes in electrical resistance as cells pass through a small aperture. It is effective for liquid samples but may not be ideal for small colonies due to potential inaccuracies with low cell concentrations.
5. Membrane filtration: This technique involves filtering the liquid sample through a membrane that traps bacteria, which can then be counted. It is particularly useful for small colonies in liquid media, as it concentrates the cells for easier counting.