BIOCHEMISTRY - Textbook - Ostapchenko L. I. - 2012

Chapter 6. AMINO ACID METABOLISM AND FUNCTIONS. PROTEIN BIOSYNTHESIS

6.10. Protein biosynthesis

One of the most fundamental tasks of modern biology and natural science as a whole is to elucidate the molecular foundations and mechanisms governing the synthesis and Regulation of Protein molecules. Today, leveraging a wide range of Methods in biochemistry and molecular biology, this enables researchers to address issues of heredity, Variability, growth, development, and even programmed Cell death in living organisms, as well as to develop means for the targeted correction of these processes.

Protein METABOLISM is a highly dynamic process. Accounting for up to 50% of the dry weight or 15–18% of the living mass of a cell, Proteins exhibit a high turnover potential. The average rate of polypeptide chain assembly in bacterial Cells reaches up to 20 amino acid residues per second, in Yeast 7–10, and in mammals 5–7. The discovery and investigation of the MOLECULAR MECHANISMS OF Protein Synthesis AND its regulation stand among the major scientific achievements of the 20th century: specifically, during the 1940s–1970s, it was established that Nucleic Acids and Proteins function as informational macromolecules, as their monomer sequences encode specific biological meaning. The nucleotide sequence of DNA determines The Structure of all cellular proteins. DNA segments that encode specific proteins (genes) are copied (transcribed) into a polynucleotide chain of messenger (mRNA), which subsequently serves as a template for protein synthesis. Thus, the Genetic information encoded in DNA (genotype) governs The formation of phenotypic traits, thereby translating genotype into phenotype. This pathway of Information Flow encompasses Three types of template-directed syntheses:

✵ DNA Synthesis — Replication (English replication — copying, duplication);

✵ RNA Synthesis — Transcription (Latin transcriptio — overwriting);

✵ protein synthesis — Translation (Latin translatio — transfer, translation).