How long is the blending step in the kiwi DNA isolation protocol?

• A. 1 second
• B. 2 seconds
• C. 5 seconds
• D. 3 seconds

Answer: (D)

Blending time tests how much mechanical disruption you apply to release DNA from the kiwi cells while trying not to damage the DNA itself. The idea is to break open enough cells so the DNA is in the solution, but not to yank on the strands so hard that they get cut into small pieces.

In this kiwi protocol, about 3 seconds of blending provides a balance: it’s long enough to disrupt cell walls and membranes and release DNA, but short enough to avoid excessive shear that would break the DNA strands. If you blend for only 1–2 seconds, you may not release enough DNA. If you blend for about 5 seconds, the DNA can be sheared into fragments, making it harder to see and obtain a good yield. So the 3-second duration is chosen to maximize release while preserving DNA integrity.