On a very simple illustration, life begins on humans at their conception. Sustain it after birth when its basic need – which is the food – is met. Life however is so complex that deeper understanding of how deoxyribonucleic acid (DNA), from the family of nucleic acids, is formed which then sustains life. Each part of the human body or any living things contains lots of cells and requires protein to make it functional and live. With the need to manufacture the various kinds of proteins, the human body must act like a machine in an industrial plant to produce what is needed to sustain life.
The synthesis of protein is initiated when a ribosome is attached to the mRNA. Once attached, coding starts and translated into a transfer RNA (tRNA). The next sequence then is elongation when tRNA brings the amino acid to the corresponding codon while the ribosomes move down the mRNA strand. The synthesis of the protein ends when the final mRNA is read and releases it. This sequence is called termination. Below is the step-by-step process of protein synthesis.
- DNA Transcription. Transcription process happens when RNA is synthesized at the DNA template. RNA molecules are synthesized by enzymes called RNA polymerase, which follows the DNA sequence. Initiation happens when RNA synthesis begins. In this sequence, RNA molecules bind to the promoter and provide opening to expose nucleotides. One exposed DNA strands makes possible in the beginning of an RNA chain. The process then is repeated, thus the RNA chain grows and becomes elongated. The process of chain elongation continues until the enzyme receives a termination signal. Once stop signal is encountered by the enzyme, the polymerase stops and releases the DNA template and the RNA chain. RNA transfer to cytoplasm happens when tRNA binds at one end to a specific codon in the mRNA and at the other end to the amino acid. This binding or attachment is important because it links covalently the amino acid to a tRNA that converts sequences of nucleotides. Another function of the amino acid attachment is essential in the formation of the peptide bond.
- DNA Translation. Translation of completely processed RNA by the ribosome starts when a specific enzyme pairs each amino acid to its appropriate tRNA molecule. Aminoacyl-tRNA synthetases are responsible in covalently linking to its appropriate set of tRNA molecules. The aminoacyl-tRNA is equally important with the tRNA molecule in the decoding process. Once amino acid is paired with the appropriate tRNA molecule, amino acids then are added to the carboxyl-terminal end of the polypeptide chain. The growing carboxyl end of the polypeptide chain is always activated due to its link to the tRNA molecule.
In the production of amino acids and proteins, the DNA undergoes a process, which is divided into two parts: transcription and translation. The nuclear DNA is transcribed into messenger RNA (mRNA) inside the nucleus, which is essential to translation. The completely processed RNA then is transported to the cytoplasm and the ribosome translates it. The translation process is so called the synthesis of proteins. Translating the mRNA codon follows a sequence, which are initiation, elongation and termination.