Replication, Transcription, and Translation

The chemical functioning of a cell is the main objective of Molecular Biology (MB). The isolation, identification, and purification of biomacromolecules could be seen as the first step, in fulfilling this objective. From the catalytic point of view, enzymes are the center of attention. However, the most important biomolecule in the cell is the DNA, in which the genetic code of each enzyme is enclosed, thus representing ultimate target for MB. The biochemical and molecular processes of replication, transcription, and translation become part of the objective. 

Keeping your direction in mind is never a bad idea, but with replication, transcription, and translation it s absolutely essential—these types of questions are just too easy to write, and you ll see them for certain... 

Figure 2.17 Schematic representation of replication, transcription, and translation.

One of the groups of theories about the origin of the genetic code states that the code has to be the way it is, and is therefore universal, for stereochemical" reasons. In other words, phenylalanine, f. ex. must be represented by the triplets UUU and UUC because phenylalanine is somehow stereochemically related to these two codons 52,53,56,57) This seems likely, since steric fit is an essential property of the processes of replication, transcription and translation. That doesn t mean that one has conclusive evidence for such a statement. It only means that the theoreticians are groping in such a direction. 

The processes of replication, transcription, and translation are illustrated schematically in Figure 2.17 and further explained in the following paragraphs. 

The central dogma of molecular biology, showing the general pathways of information flow via replication, transcription, and translation. The term "dogma" is a misnomer. Introduced by Francis Crick at a time when little evidence supported these ideas, the dogma has become a well-established principle. 

It is now understood that the replication of DNA and virtually every step in the utilization of the genetic code require metal ions in some way. The three fundamental steps of replication, transcription and translation are influenced by metal complexation."3,129,130... 

The central dogma of molecular genetics The central dogma was based upon the findings of Watson and Crick and states that the flow of information is essentially in one direction from DNA to protein. Three major steps can be defined in the process replication, transcription and translation of genetic material, as shown in Fig. 5.A9. 

Viruses borrow heavily on the host enzymatic machinery to obtain energy for synthesis, as well as for replication, transcription, and translation. The virus infective cycle is strongly irreversible. Virus infection is followed by the gradual turning on of viral genes. Viral enzymes are the first viral gene products in late infection, the virus structural proteins are favored. The irreversible lytic cycle of the virus is directed by a cascade of controls. 

The flow of genetic information involves biosyntheses of DNA, RNA, and proteins, known as replication, transcription, and translation, respectively. DNA replication in prokaryotes (Nossal, 1983) and eukaryotes (Campbell, 1985) are very similar, though eukaryotic replication is more complex (DePamphilis, 1996). A... 

The chapter begins with a discussion of the structure of nucleosides and nucleotides. Then the structure of the nucleic acids, DNA and RNA. the polymers formed from nucleotide monomers, is presented. The function of these polymers in the replication, transcription, and translation of genetic information is briefly addressed. Next, the organic chemistry involved in determining the sequence of DNA is presented. Finally, the synthesis of small DNA molecules in the laboratory is discussed. 

Understanding the General Features of Replication, Transcription, and Translation... 

Replication, transcription and translation are the three processes that are responsible for carrying out the central dogma. 

The key events that occur in the formation of DNA, RNA and protein are called REPLICATION, TRANSCRIPTION, and TRANSLATION, respectively ... 

Although the majority of drugs act on protein structures, there are several examples of important drugs which act directly on nucleic acids to disrupt replication, transcription, and translation. 

Magnesium is the fourth most abundant cation in the body after sodium, potassium, and calcium, and is the second most abundant cation in intracellular fluid after K+ Mg + is needed in many enzymatic reactions, particularly those in which ATP Mg + is a substrate. Magnesium binds to other nucleotide phosphates and to nucleic acids and is required for DNA replication, transcription, and translation. The DNA helix is stabilized by binding... 

Zinc is an essential component of a large number of enzymes. Zinc-containing enzymes are involved in the synthesis and degradation of major metabolites, and serve to regulate the replication, transcription, and translation of genetic material. In some proteins zinc binds with a coordination number of 4 to sulfur and nitrogen, while in others in which it also binds oxygen the coordination number is S or 6. 

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