Question

A northern blot differs from a Southern blot in the ______

A) presence or absence of a nitrocellulose membrane.
B) type of probe used.
C) size of the genetic sequences involved.
D) type of nucleic acid being isolated.
E) number of genetic sequences detected.

Answer 1

The difference between a northern blot and a Southern blot lies in the type of nucleic acid being isolated(D); the northern blot identifies RNA, typically mRNA for studying gene expression, whereas the Southern blot identifies DNA.

Step-by-step explanation:

A northern blot differs from a Southern blot in the type of nucleic acid being isolated(D). In Southern blotting, DNA is the nucleic acid of interest, while in northern blotting, RNA is immobilized on the membrane and probed. The key purpose of a northern blot is to detect the presence and amount of mRNA expressed, which serves as an indicator of gene expression within a sample. It is an essential technique for studying gene expression patterns in various tissues or under different experimental conditions. Southern blots, on the other hand, are used to identify specific DNA sequences within a sample.