The diagram of protein synthesis process shows a ribosome and mRNA. A protein synthesis diagram shows the sequential process of DNA transcription to mRNA in the nucleus, followed by mRNA processing and export into the cytoplasm. There ribosomes attach to mRNA and facilitate translation, with tRNA molecules carrying amino acids to match mRNA codons. The diagram of protein synthesis in class 12 helps students understand this process easily.

The well-labelled diagram of protein synthesis is shown below with the stages:

Diagram of Protein Synthesis

Protein Synthesis

Protein synthesis is a fundamental process in living organisms, essential for cell growth, development, and its functioning. It occurs in two main stages: transcription and translation. The stages of protein synthesis are mentioned below:

Transcription

Transcription start in the cell nucleus, where DNA serves as the template for the synthesis of messenger RNA (mRNA). The enzyme RNA polymerase binds to the promoter region of a gene on the DNA molecule, unwinding and separating the DNA strands. Using one of the strands as a template, RNA polymerase synthesizes a complementary mRNA molecule by adding nucleotides according to the base-pairing rules (A-U and G-C). Once transcription is complete, the mRNA transcript detaches from the DNA and undergoes processing, including the addition of a 5′ cap and a poly-A tail (polyadenylation) and the removal of introns (non-coding regions). The mature mRNA molecule then exits the nucleus and enters the cytoplasm.

Translation

Translation occurs in the cytoplasm and involves the conversion of the mRNA sequence into a polypeptide chain, or protein. The mRNA attaches to a ribosome, where the process begins. The protein synthesis diagram shows that translation involves three key steps: initiation, elongation, and termination. During initiation, the small ribosomal subunit binds to the mRNA molecule, and the initiator tRNA, carrying the amino acid methionine, binds to the start codon (AUG) on the mRNA. The large ribosomal subunit then joins, forming a functional ribosome.

In the elongation phase, the ribosome moves along the mRNA molecule, reading the codons in a sequential fashion. Each codon specifies a particular amino acid, and the corresponding tRNA molecule, carrying the complementary anticodon and the corresponding amino acid, binds to the mRNA codon via base pairing. The ribosome catalyzes the formation of peptide bonds between adjacent amino acids, forming a growing polypeptide chain.

Termination

Termination occurs when a stop codon (UAA, UAG, or UGA) is encountered on the mRNA. This signals the end of protein synthesis, and the completed polypeptide chain is released from the ribosome. The newly synthesized protein may undergo further modifications and folding before achieving its functional conformation.

Conclusion – Diagram of Protein Synthesis

Protein synthesis, occurs stages through transcription and translation, & it is essential for cellular function. This complex process translates genetic information into proteins, crucial for life’s processes. The diagram of protein synthesis shows step by step the process by which genetic information encoded in DNA is transcribed into mRNA and translated into proteins.

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