Biochemical Engineering Fundamentals, Part 1 - Bailey J., Ollis D. 1989

Molecular Genetics and Regulatory Systems
Molecular Genetics

In the preceding chapters, we examined The kinetics of enzyme catalysis and the Selection/11.html">General features of some of the most common metabolic pathways. While any chemical plant synthesizes a limited number of substances and the steady-state operation of reactors (which is usually the goal) requires minimal regulation, the living Cell is an infinitely more complex chemical complex operating in a perpetual state of flux. As a cell progresses through the various periods and stages of its life cycle, the concentrations and relative proportions of substrates, enzyme catalysts, RNA, Cofactors, and other components undergo continuous change. This chapter is devoted to exploring the synthesis and Regulation of the systems that govern cellular dynamics. This topic is closely intertwined with the issues of viral infection in cell cultures, natural and artificially induced Mutations, genetic transformations, and the metabolic versatility of certain cultures regarding available nutrients.

Before delving into cellular genetics and the molecular expression of Genetic information, we must briefly revisit the Composition and Structure of DNA, the three Major Types of RNA, and Proteins, as discussed in Chapter 2. To appreciate The Significance of the mechanisms explored below, it is helpful to recall that proteins—particularly Enzymes—directly shape cellular function by regulating the Chemical Reactions taking place within The Cell. Consequently, to a large extent, the Complement of cellular enzymes (the types of enzymes and the concentration of each) dictates metabolic processes, meaning The Nature and pattern of sequential and parallel reactions occurring in the cell. Other proteins also perform vital cellular Functions (refer to Table 2.6). Clearly, any daughter cell must inherit from its parent cell all the genetic information required to synthesize the exact same proteins found in the original cell. The mechanisms governing the transmission of this information are the domain of genetics. In the first section of this chapter, we will explore how The nucleotide sequence of a unique and therefore informational biopolymer—deoxyribonucleic acid (DNA)—dictates the course of Protein Synthesis within the cell.