Protein+Synthesis


 * Basic Information**

A protein is a molecule made from one or more amino acids. They are also called polypeptides because the chains of amino acids are linked by peptide covalent bonds. Proteins are very important to the cell they are involved in replicating DNA, responding to stimuli,and transporting molecules from one place to another (Alberts, Johnson, Lewis, et al. 2002). This is vital to cellular physiology because this where the cells get there proteins to execute their specific functions which are crucial for the survival of the organism. Proteins are synthesized through mechanical and chemical processes. DNA and and RNA, including mRNA (messenger RNA), tRNA (transfer RNA), rRNa (Ribosomal RNA), SRP RNA ( Signal Recognition Particle RNA), and tmRNA ( Transfer Messenger RNA ) are involved in this process (Alberts, Johnson, Lewis, et al. 2002). Figure One: Step by step process of protein synthesis

As seen in the figure above, Protein Synthesis starts off by enzymes in the nucleus unwinding the need section of DNA so it can make RNA, which then duplicates one side of the DNA strand and is transferred to different parts of the cell to help bring together the amino acids that form proteins. This is called mRNA (messenger RNA), which is located in the nuclear pores and moves to the cytoplasm. Once the mRNA exists the nucleus, protein synthesis actually takes place and the mRNA binds to a ribosomal subunit which triggers transfer RNA. The tRNA binds to the mRNA and when the second strand of tRNA binds to its amino acid it forms ATP. (Alberts, 2008).This sequence then begins to repeat itself and the chain of amino acids grows longer. Protein synthesis is complete when the amino acids are in place (Alberts, 2008). . Hundreds of proteins are synthesized each second and protein synthesis takes place in numerous ribosomes in the cell. Researchers discovered the process of protein synthesis by studying the evolutionary origins of the secondary structure of the small and large ribosomal subunits (Caetano-Anollés,2002). This study contributed to three monophyletic groups which consist of Eucarya, Archaea, and Bacteria and through evolution of the ribosomal characters showed that transfer rNA binding domains in the larger rNA subunit evolved with the rest of the rNA molecules which provides insight to the evolution of nucleic acids and protein synthesis (Caetano-Anollés,2002).

Here is also a video exemplifying protein synthesis http://www.youtube.com/watch?v=Ikq9AcBcohA

Bibliography Alberts, Bruce. //Molecular Biology of the Cell//. 5th Edition. New York: Garland Science; 2008. From RNA to protein. Alberts B, Johnson A, Lewis J, et al. //Molecular Biology of the Cell//. 4th edition. New York: Garland Science; 2002. Protein Function. Available from: http://www.ncbi.nlm.nih.gov/books/NBK26911/ Caetano-Anollés, G. (2002). Evolved RNA secondary structure and the rooting of the universal tree of life. //Journal Of Molecular Evolution//, //54//(3), 333-345.