Glucose can also be absorbed by an active process which requires metabolic energy. What is the immediate source of this energy in cells?

Explanation:

The DNA contains many regulatory sequences that are very important, even though they do not code for proteins.

For example, the expression of every gene is regulated by a region called the Promoter. The promoter sequence, located close by the coding region of the gene, usually binds the RNA polymerase (the enzyme that transcribes genes into mRNA) as well as other proteins necessary for transcription,

The promoter sequence, thus, does not itself code for proteins, but is essential for transcription and must be highly conserved so that the RNA polymerase can find it.