The three types of RNA discussed are messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA). mRNA forms during transcription when RNA polymerase synthesizes RNA from the DNA template. Post-transcriptional modification is required for the mRNA to mature and exit the nucleus. Once in the cytoplasm, the mRNA will bind to a ribosome composed of rRNA and proteins. The ribosome will then recruit tRNA molecules to the complex in order to synthesize the protein product. Each amino acid binds to a specific kind of tRNA. tRNA brings the amino acids to the growing end of the newly forming polypeptide at the ribosome by binding to the codon of the mRNA.

The anticodon of any codon will be the RNA nucleotides that complement the codon sequence. In RNA, adenine (A) complements uracil (U) while cytosine (C) complements guanine (G). Hence, for the codon 5' AUG 3', the complements will be 3' UAC 5'. Note that many of the incorrect answers contain thymine (T), a nucleotide not found in RNA.

Each tRNA contains the anticodon for a specific mRNA codon and carries the amino acid corresponding to that codon to ribosomes during translation. mRNA is produced by transcription from DNA, and ribosomes translate it into proteins. Multiple codons can code for a single amino acid, and so there can be several tRNA anticodons that could be used for a single amino acid.

mRNA, tRNA, and rRNA all play a key role in the synthesis of proteins. tRNA (transfer RNA) is responsible for gathering amino acids in the cytosol and bringing them to the ribosomes when translation is taking place. mRNA (messenger RNA) is the template for translation. rRNA (ribosomal RNA) is a structural element of the ribosomes.

Ribosomes are non-membranous organelles that direct protein synthesis by reading mRNA and joining amino acids into strands of polypeptides. Ribosomes exist in both free and membrane-bound states. They are synthesized in both the nucleolus and cytoplasm. The components that make up these non-membranous organelles are rRNA molecules and a variety of proteins. Ribosomes have a large and a small subunit, together called the translational apparatus. The small ribosomal subunit reads the mRNA strand and the large ribosomal subunit joins amino acids into polypeptides.

The start codon for any strand of RNA begins with the codon that codes for the amino acid methionine. This is the first amino acid in a polypeptide chain. The abbreviation for methionine is: Met.

The large ribosomal subunit has three sites that interact with tRNA molecules—the peptidyl “P” site, the aminoacyl “A” site, and the exit “E” site. The P-site holds the tRNA corresponding to the most recently added amino acid, which is attached to the growing polypeptide chain by a peptide bond. The A-site holds the tRNA with the next amino acid to be added to the chain. Finally, the E-site holds the free tRNA without an amino acid that was previously in the P-site.

In messenger RNA, each codon is three nucleotides that codes for a particular amino acid during translation. Purines and pyrimidines are types of nucleotides on DNA and RNA. The genetic code is redundant, but each codon only codes for one amino acid.

Anticodons are found on molecules of tRNA. Their function is to base pair with the codon on a strand of mRNA during translation. This action ensures that the correct amino acid will be added to the growing polypeptide chain. A tRNA molecule will enter the ribosome bound to an amino acid. The anticodon sequence will bind to the codon of the mRNA, allowing the tRNA to release the attached amino acid. This amino acid is then added to the peptide chain by the ribosome.

Amino acid sequence is determined by the sequence of codons on mRNA. tRNA is responsible for bringing new amino acids to the ribosome. Interactions between the codons on mRNA and the anticodons on tRNA are what allow the formation of the appropriate peptide bonds.

Chaperones are later used to facilitate the development of protein structure, but are not involved in checking protein sequence.