Answer: The mRNA chain is complementry to the DNA molecule and yet it is not identical to it
Explanation:
Expression of a gene implies manufacturing its corresponding protein. It is a multilayered process and this multilayered process has two maib steps. In the first step, the information in DNA is transferred to a messenger RNA (mRNA) molecule by way of a process called transcription. In the transcription process, the DNA of a gene serves as a template for complementary base-pairing, and an enzyme called RNA polymerase II catalyzes the formation of a pre-mRNA molecule, which is then processed and results in the formation of mature mRNA.
The resulting mRNA is a single-stranded copy of the gene, which next must be translated into a protein molecule. During translation, which is the second main step in gene expression, the mRNA is "read" according to the genetic code, which relates the DNA sequence to the amino acid sequence in proteins. Each group of three bases in mRNA comprises of a codon, and each codon specifies a particular amino acid. The mRNA sequence is thus used as a template to assemble in order the chain of amino acids that form a protein. This portion of mRNA is located in between the first nucleotide that is transcribed and the start codon (AUG) of the coding region, and it doesn't affect the sequence of amino acids in a protein.
