Question

Which of the following statements is NOT true regarding a cDNA library?

A: It is derived from messenger RNAs that are present in a cell.
B: It contains all of the DNA sequences of a species.
C: It is a collection of cloned DNA fragments.
D: It contains DNA for the genes that are active within a cell.
E: It cannot be directly compared to the sequences found in genomic libraries.

Answer 1

Option B is incorrect because a cDNA library does not contain all DNA sequences of a species, but only those that are actively expressed and transcribed into mRNA.

Step-by-step explanation:

The statement that is NOT true regarding a cDNA library is B: It contains all of the DNA sequences of a species. A cDNA library is derived from messenger RNAs (mRNAs) present in a cell and represents only the genes that are actively being expressed at the time the library is created, not the entire genome. It is a collection of cloned DNA fragments translated into proteins and active within a cell, excluding introns and regulatory sequences found only in genomic DNA.