Which type of molecule is mRNA?

mRNA, or messenger RNA, plays a crucial role in the process of gene expression. It is synthesized during transcription, where the DNA sequence of a gene is transcribed into a complementary RNA strand. The primary function of mRNA is to serve as a template for translation, which is the process through which proteins are synthesized. The information encoded in the mRNA sequence is used by ribosomes to assemble amino acids in the correct order, thus translating the genetic code into functional proteins.

In contrast, other types of RNA serve different functions within the cell. Ribosomal RNA (rRNA) is a component of ribosomes and helps facilitate the translation of mRNA into proteins. Transfer RNA (tRNA) is responsible for carrying specific amino acids to the ribosome, where they are added to the growing polypeptide chain during protein synthesis. Nucleosomal RNA does not refer to a commonly recognized type of RNA and does not play a direct role in translation or protein synthesis. Thus, the designation of mRNA as messenger RNA is crucial as it highlights its specific role in relaying genetic information from DNA to the protein-synthesis machinery.