Question

what are the functions of the lysis solution, salt, and alcohol in the extraction of dna performed in this exercise?lysis - breaks open cells to release dnasalt - neutralizes dnas charge for precipitationalcohol - precipitates dna by reducing its solubilityquestion 2why was the dna sample centrifuged first before the purification step and then secondly after the purification step in this exercise?

Explanation:

Centrifugation before purification: Separates cellular debris from DNA solution. Heavier debris settles at the bottom, leaving DNA in the supernatant.
Centrifugation after purification: Precipitates purified DNA. Alcohol - treated DNA forms a pellet at the bottom upon centrifugation, further isolating it from remaining impurities.

Answer:

Centrifugation before purification separates cellular debris from the DNA solution. Centrifugation after purification precipitates the purified DNA.