Describe the role of mRNA and IRNA during protein synthesis.

During protein synthesis, both messenger RNA (mRNA) and transfer RNA (tRNA) play crucial roles in translating genetic information into functional proteins. Here’s a detailed description of their roles: ### mRNA (Messenger RNA) 1. **Transcription**: - mRNA is synthesized from a DNA template during the process of transcription. This occurs in the nucleus of eukaryotic cells. - The enzyme RNA polymerase binds to the DNA and unwinds the double helix, synthesizing a single strand of RNA that is complementary to the DNA template. 2. **Processing**: - In eukaryotes, the initial mRNA transcript (pre-mRNA) undergoes several modifications before it can be translated. This includes the addition of a 5' cap, polyadenylation at the 3' end, and splicing to remove introns (non-coding regions). - The mature mRNA then exits the nucleus and enters the cytoplasm. 3. **Translation**: - The mRNA serves as a template for protein synthesis during translation. It carries the genetic code in the form of codons, which are sequences of three nucleotides that correspond to specific amino acids. ### tRNA (Transfer RNA) 1. **Amino Acid Transport**: - tRNA molecules are responsible for bringing the appropriate amino acids to the ribosome during protein synthesis. Each tRNA is specific to one amino acid and has an anticodon that is complementary to the mRNA codon. 2. **Anticodon-Codon Pairing**: - During translation, the ribosome facilitates the pairing of tRNA anticodons with mRNA codons. This ensures that the correct amino acid is added to the growing polypeptide chain according to the sequence specified by the mRNA. 3. **Peptide Bond Formation**: - Once the tRNA is bound to the ribosome and the mRNA, the ribosome catalyzes the formation of peptide bonds between adjacent amino acids, linking them together to form a polypeptide chain. 4. **Release and Recycling**: - After the amino acid is added to the polypeptide chain, the tRNA is released from the ribosome and can be recharged with another amino acid, ready to participate in another round of protein synthesis. ### Summary In summary, mRNA serves as the template that carries the genetic information from DNA to the ribosome, where it is translated into a protein. tRNA acts as the adaptor that translates the mRNA codons into the corresponding amino acids, facilitating the assembly of the protein. Together, mRNA and tRNA are essential for the accurate and efficient synthesis of proteins in all living cells.