RNA is short for RiboNucleic Acid and they are single-stranded chains of nucleic acids that consist of nucleotides and their bases - adenine, guanine, uracil, and cytosine. RNA's job is to transcript, translate, and decode genetic codes to synthesize proteins.
There are three main types of RNA molecules:
mRNA - (Messenger RNA) - They are a major part of the transcription of DeoxyriboNucleic Acid (DNA). Transcription is copying down the genetic info from the DNA into RNA format for protein synthesizing.
tRNA - (Transfer RNA) - They are highly responsible for the translation of protein synthesis. They have to 'translate' the nucleotide sequence of mRNA into an amino acid sequence that will later come together to form a protein.
rRNA - (Ribosomal RNA) - They assemble proteins to form ribosomes. They move along an mRNA molecule and catalyze those amino acids into chains of protein, as well as bind tRNA and other molecules for protein synthesis.