Question

Put in order the following buffers to be used during the column purification of plasmid DNA:

1. N4 (neutralization)
2. R3 (solubilization)
3. L7 (lyses)
4. TE (elution)
5. W9 (wash)
A. 2,1,3,4,5
B. 1,3,2,5,4
C. 2,3,1,5,4
D. 3,2,1,5,4

Answer 1

The correct sequence for column purification of plasmid DNA is lysis (L3), solubilization (R3), neutralization (N4), wash (W9), and elution (TE), which corresponds to option D: 3,2,1,5,4.

Step-by-step explanation:

The correct order of buffers for column purification of plasmid DNA is: L7 (lysis), R3 (solubilization), N4 (neutralization), W9 (wash), and finally TE (elution). This follows the typical workflow of lysis to release the plasmid DNA from the host cells, solubilization of cellular components, neutralization to allow DNA to bind to the column, washing to remove impurities, and elution to collect the purified plasmid DNA.

As such, the correct sequence of these steps is option D: 3,2,1,5,4 (L7, R3, N4, W9, TE). In a standard plasmid purification protocol, lysis (L7) breaks the cell open and releases the DNA; solubilization (R3) ensures that cell debris is solubilized; neutralization (N4) allows the plasmid DNA to bind to the column; washing (W9) removes remaining impurities; and elution (TE) releases the purified plasmid DNA from the column for collection and use.