Lab Techniques—Typical Volumes in Molecular Biology In routine molecular biology workflows (PCR setup, cloning, enzyme digests), the most common liquid volumes are measured in which unit?

Introduction / Context:
Molecular biology experiments usually handle small reaction volumes to conserve reagents and fit microtube formats. Accurate volume measurement is central to reproducibility and enzyme kinetics.

Given Data / Assumptions:

• Typical PCR volumes: 10–50 μl.
• Restriction digests/ligation: 10–20 μl.
• Micro-pipettes are calibrated for μl ranges (e.g., P10, P20, P200, P1000).

Concept / Approach:
Relate standard protocol volumes to units. Although nanoliter stages exist (e.g., robotics, qPCR droplets), most hands-on benchtop methods use microliter volumes. Milliliter volumes are common for culture media but not for reaction mixes.

Step-by-Step Solution:

Verification / Alternative check:
Vendor protocols for polymerases and ligases specify reagent additions in μl.

Why Other Options Are Wrong:

• ml/l/dl: too large for typical reactions.
• nl: used in specialized platforms, not the most common at the bench.

Common Pitfalls:
Confusing culture volumes (ml) with reaction volumes (μl).

Final Answer:
μl (microliters)