How is RNA used to make proteins?

RNA is used to make proteins through transcription and translation. The three main types of RNA involved in this process are: mRNA, rRNA, and tRNA. mRNA carries the genetic information from the DNA to the ribosomes. rRNA forms an integral part of the ribosomes, where proteins are assembled. tRNA helps in bringing the amino acids to the ribosomes according to the instructions carried by the mRNA. 

During transcription, the DNA double helix unwinds and RNA polymerase synthesizes a complementary RNA strand based on the DNA template. This mRNA carries the genetic code from the DNA to the ribosomes in the cytoplasm. The process of translation occurs in three main stages: initiation, translation, and termination. During initiation, the ribosome assembles on the mRNA, and the first tRNA (carrying the amino acid methionine) binds to the start codon (AUG) on the mRNA. In elongation, successive tRNA molecules bring amino acids to the ribosome, where they are linked together to form a growing polypeptide chain. This process continues until a stop codon is reached. During termination, a stop codon is encountered on the mRNA and the ribosome releases the completed polypeptide chain. The newly synthesized protein is then released into the cell.