Question

an mi student is using a p20 micropipette to add restriction enzyme to a dna sample. when measuring the restriction enzyme, which of the steps listed below should she do first? press her thumb to the second (hard) stop place the pipette tip in the restriction enzyme container press her thumb to the first stop

Explanation:

When using a micropipette, the first step is to press the thumb to the first stop. This creates a vacuum to draw up the liquid. Pressing to the second stop is for dispensing. Placing the tip in the container is after pressing the first stop.

Answer:

press her thumb to the first stop