Question

Purified DNA ultimately precipitates after the addition of chilled ethanol. This DNA that separate out can be removed by
A)Electrophoresis
B)Downstream processing
C)PCR
D)Spooling

Answer 1

Hint: DNA is Deoxyribonucleic Acid. It's the genetic material which consists of two strands winding around each other to create a shape called a helix. Each strand includes a backbone made up of alternating sugar and phosphate groups. Attached to every sugar is one in every of four base-adenine (A), cytosine (C), guanine (G), and thymine (T).

Complete answer:
The protocols for extraction of DNA vary considerably to account for the unique characteristics of specific samples. The general steps include homogenization, lysis, digestion, separation and collection. This procedure is carried out best in a small glass or plastic tube.

The sample is blended thoroughly to separate cells from each other. This allows the cell ingredients more accessible to reagents which follow. Then, detergent or enzymes are added to the homogenate to lyse cell membranes and free the DNA. At this point, DNA is surrounded by proteins, lipids, carbohydrates. Further, enzymatic digestion may be done that helps to break down proteins so that they do not bind to DNA or interfere with its collection. DNA is separated from cell contents by the addition of cold, pure, ethyl or isopropyl alcohol. Since DNA is not soluble in these alcohols therefore, it will condense to try and minimize its contact with alcohol. The condensed DNA is collected by centrifugation or spooling.

Hence, the correct answer is option (C)

Note: DNA collection by spooling is mostly effective when a large amount of DNA is obtained by the procedure of extraction. It is also an important demonstration method as the impressive tangle of pure DNA is visible clearly.