Protein Synthesis

Protein synthesis is one of the most fundamental biological processes. To start off, a protein is made in a ribosome. There are many cellular mechanisms involved with protein synthesis. Before the process of protein synthesis can be described, a person must know what proteins are made out of. There are four basic levels of protein organization. The first is primary structure, followed by secondary structure, then tertiary structure, and the last level is quaternary structure. Once someone understands the makeup of a protein, they can then begin to learn how elements can combine and go from genes to protein. There are two main processes that occur during protein synthesis, or peptide formation. One is transcription and the other is translation. Although these biological processes slightly differ for eukaryotes and prokaryotes, they are the basic mechanisms for which proteins are formed in all living organisms. There are four main levels of a protein, which make up its native conformation. The first level, primary structure, is just the basic order of all the amino acids. The amino acids are held together by strong peptide bonds. The next level of protein organization is the secondary structure. This is where the primary structure is repeated folded so that it takes up less space. There are two types of folding, the first of which is beta-pleated sheets, where the primary structure would resemble continuous spikes forming a horizontal strip. The second type of folding is an alpha helix, which goes vertically forming a wavy line. An alpha helix is in the same shape of one strand of DNA. These new formations are held together by hydrogen bonds. The third level is the tertiary structure. The tertiary structure of a protein is a contorted secondary structure being twisted and folded all out of shape to form a 3-d complex. The type of bonding that holds these formations together are weak interactions such as hydrophilic, hydrophobic, ionic, and hydrogen bonds. These bonds are individually weak, but collectively strong. The forth level, which completes a protein, is quaternary structure, which occurs when two or more tertiary structures are joined together by polypeptide bonds. The formation of a protein begins in the genes, which contain the basic building information for all parts of living organisms. There are four DNA nucleotides that make up genes: A, T, C, and G. A codon is any arrangement of three of these nucleotides. Each triplet of nucleotides codes for one amino acid. First transcription will begin in the nucleus where mRNA will transcribe the DNA template. During both transcription and translation, there are three steps. The first step in transcription is initiation where RNA polymerase separates a DNA strand and binds RNA nucleotides to the DNA. RNA nucleotides are the same as DNA ones except that U replaces the T. The second is just the elongation of the mRNA. The third step of transcription is termination. This occurs when RNA polymerase reads a codon region and the mRNA separates from the DNA terminating the sequence. There are special codon triplets, known as start and stop codons, which begin and end the process of transcription. At the end of transcription translation will begin except for in prokaryotes where transcription and translation can go on at the same time because of the lack of a defined nucleus. The second part in protein synthesis is translation. Translation occurs in the cytoplasm and follows the same three steps as that of transcription with slight variations. There are three stages in translating a mRNA code into a protein and each of which requires enzymes and proteins. Each tRNA carries a specific amino acid that bonds to the anticodon. Initiation begins the process as the sequence UAC is read off and connected to a tRNA. The second step is once again elongation where first there is codon recognition, followed by peptide born formation, and then to end this stage, there is translocation. The final step of protein synthesis is the termination of translation where a stop codon is read ending the process. Protein Synthesis is a basic fundamental process for multiple reasons. One is that the process is common to almost all living organisms, showing that it is one of the first processes to develop, before organisms began to brake off into different evolutionary tracks. Another reason why it is such a basic process is because of the functions that a protein carries out. A protein gives structural support, provides storage, it can signal things, forms antibodies and enzymes, and can transport substances, such as hemoglobin which carries oxygen in a human's blood. The most important reason why protein synthesis is a fundamental biological process is because without it, all living organisms would die.