Nucleic acids Macromolecules with replication

This difference between the two divisions of biologically important polymers is also reflected in the likelihood that there are two molecules with the exact same structure. For molecules such as polysaccharides and those based on terpene-like structures the precise structures of individual molecules vary, but for proteins and nucleic acids the structures are identical from molecule to molecule. This can be considered a consequence of the general function of the macromolecule. For polysaccharides the major, though not the sole, functions are energy and structure. For proteins and nucleic acids, the main functions include memory and replication, in addition to proteins sometimes also serving a structural function. 

The antipsychotic agents are known to precipitate proteins and may coprecipitate polynucleotides so they can no longer participate in nucleic acid synthesis. Chlorpromazme also increases the loss of macromolecules from the intracellular pools that are essential for cellular replication. When the hone marrow from a patient with phenothiazine-induced agranulocytosis is examined, it initially appears to have no cellularity (aplastic), hut over time it becomes hyperplastic. It is believed that toxic effects of the phenothiazines are not seen in all patients taking the medications because the majority of patients have enough bone marrow reserve to overcome the toxic effects. ... 

The central dogma of molecular biology has traditionally posited that nucleic acids alone function as genetic determinants because these macromolecules can template their own replication. The prion or protein-only hypothesis expands the central dogma to include proteins as etiologic agents for disease transmission (Griffith, 1967 Prusiner 1982) and elements of inheritance for phenotypic traits (Wickner, 1994). Prions are unique proteins that can exist in more than one stable conformation, and at least one of these states can be transmitted to newly synthesized protein as a form of templated replication. Since each physical state is associated with a distinct phenotypic state, the trait becomes heritable. 

Abstract Replication is a fundamental process that is critical to life as we know it. While replication today is carried out by complex biochemical machineries that have been evolving for bilhons of years, it must have originated with relatively small molecules in simple systems. Here we explore this concept, focusing on the physicochemical characteristics and prebiotic potential of two classes of biological macromolecules nucleic acids and lipids. We discuss the informational and catalytic capabilities of DNA and RNA, the thermodynamic limits of information transfer, the structure and function of lipid membranes, and the formation and maintenance of primitive protocells . 

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