A direct cell count determines the number of ______ in a sample.

• A. biomass
• B. individual cells
• C. colony-forming units
• D. metabolic products

Answer: (B)

Verified step by step guidance

1. Understand the concept of a direct cell count: it involves counting the actual number of individual cells present in a sample, typically using a microscope and a counting chamber such as a hemocytometer.
2. Recognize that 'biomass' refers to the total mass of living material, which is not directly measured by counting cells but rather by weighing or estimating mass.
3. Know that 'colony-forming units' (CFUs) represent the number of viable cells capable of forming colonies on a growth medium, which is determined by plating techniques, not direct counting.
4. Identify that 'metabolic products' are substances produced by cells during metabolism, which are measured by biochemical assays rather than counting cells.
5. Conclude that a direct cell count specifically measures the number of individual cells in a sample, distinguishing it from other methods that estimate viability or metabolic activity.