As you might know, proteins are large biological molecules that perform different functions within our body, like catalyzing metabolic reactions or responding to stimuli or replicating DNA, but before a protein is expressed or produced, relevant parts of its genetic code present in the DNA are copied into the messenger RNA, so this messenger RNA has instructions on how to build a specific protein, and potentially it can build hundreds of proteins, but the one that tells them when to build them and how many to build are microRNAs.
Например, они ускоряют метаболические реакции, реагируют на раздражители, копируют ДНК. Перед тем, как происходит экспрессия или выработка белка, участки его генетического кода, находящиеся в ДНК, копируются в матричную РНК.