What is primarily produced during gene expression?

During gene expression, the primary molecule that is produced is RNA. The process of gene expression begins with transcription, where the information in a gene (a segment of DNA) is copied into messenger RNA (mRNA). This mRNA then undergoes processing before being translated into a protein. The translation of mRNA involves converting the sequence of nucleotides into a sequence of amino acids, which are the building blocks of proteins.

While proteins are the ultimate product of gene expression, it is crucial to note that RNA serves as the intermediary that carries the genetic information from DNA to the site of protein synthesis. Therefore, in terms of what is predominantly produced first during gene expression, RNA is the correct answer. Proteins are synthesized as a subsequent step in the process, following the production of RNA.