The molecule that brings amino acids to the ribosomes to be assembled into proteins are known as tRNAs (transfer RNAs). RNA molecules are of three types:
1) mRNA (messenger RNA)
2) tRNA
3) rRNA (ribosomal RNA)
All these three RNA molecules help in protein synthesis i.e. translation.
mRNA gets the message from the DNA to make a protein with a particular amino acid sequence. rRNA on the other hand provides the site for the synthesis of a particular protein whereas tRNA brings the amino acids from the cytosol to the site of protein synthesis. mRNA, tRNA and rRNA basically form a complex so as to accomplish protein synthesis.
