Promoters are regulatory regions of DNA located upstream (toward the 5' end) of the gene they control, and they play a crucial role in gene expression by facilitating the binding of RNA polymerase and other transcription factors.
So, the correct option is (A): Promoter
Study the given molecular structure of double-stranded polynucleotide chain of DNA and answer the questions that follow. 
(a) How many phosphodiester bonds are present in the given double-stranded polynucleotide chain? 
(b) How many base pairs are there in each helical turn of double helix structure of DNA? Also write the distance between a base pair in a helix. 
(c) In addition to H-bonds, what confers additional stability to the helical structure of DNA?
Use the given information to select the amino acid attached to the 3′ end of tRNA during the process of translation, if the coding strand of the structural gene being transcribed has the nucleotide sequence TAC. 
 
Student to attempt either option-(A) or (B): 
(A) Write the features a molecule should have to act as a genetic material. In the light of the above features, evaluate and justify the suitability of the molecule that is preferred as an ideal genetic material. 
OR 
(B) Differentiate between the following:
The output (Y) of the given logic implementation is similar to the output of an/a  …………. gate.
The very first stage of gene expression is the procedure of transcription. In this procedure, mRNA is the place where the genetic information is stored which later aids in encoding a protein. In this process, the DNA strand acts as a guide in the making of mRNA. Despite the fact that there is one exception which is adenine base pairs with uracil instead of thymine.
The transcription unit is a set of freshly combined RNA molecules that have been transcribed from DNA. The cause is to encode at least one gene. A protein that has been encoded or encrypted with a DNA transcription unit may have a coding sequence. Transcription has a lower copying fidelity rate when differentiated from DNA replication.
The procedure of transcription is enzymatically catalyzed into three steps: