Messenger RNA, or mRNA, is responsible for carrying coding sequences for protein synthesis. Containing coding sequences called transcripts, mRNA aids in the production of complimentary segments of RNA, which attach to a single strand of DNA during transcription, according to Nature Education.
Within the majority of multicellular organisms, each cell carries the genetic material for the organism, but the function of the cell varies. The function of the cell determines the need for gene expression of the cell. DNA is a double helix formation of molecules called nucleotides, made up of thymine, adenine, cytosine and guanine. During cell division, the double helix of DNA separates, allowing another complimentary segment to attach to the new single strands. Complimentary base pairing matches adenine to thymine and guanine to cytosine, reports Nature Education.
RNA enzymes called polymerases construct single-stranded RNA molecules, which also contain genetic material. When the pieces fit together during transcription, folding structures form instead of helical structures. The nucleotides from RNA pair with a single strand of DNA, matching the nucleotides. However, in RNA, the nucleotide uracil replaces thymine, notes Nature Education.
Three broad classes of RNA, messenger, ribosomal and transfer, contribute to gene expression within DNA. Of these, mRNA is the most varied type of RNA molecule. Within one cell, thousands of mRNA molecules or a single segment of mRNA may exist. More mRNA molecules gather in the more complex structures, such as structural proteins. Less complex structures, such as signaling proteins, may require just one mRNA molecule to carry out the function, explains Nature Education.