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Nucleic living systems

The major classes of organic compounds common to living systems are lipids pro terns nucleic acids and carbohydrates Carbohydrates are very familiar to us— we call many of them sugars They make up a substantial portion of the food we eat and provide most of the energy that keeps the human engine running Carbohy drates are structural components of the walls of plant cells and the wood of trees Genetic information is stored and transferred by way of nucleic acids specialized derivatives of carbohydrates which we 11 examine m more detail m Chapter 28... [Pg.1026]

Biopolymers are the naturally occurring macromolecular materials that are the components of all living systems. There are three principal categories of biopolymers, each of which is the topic of a separate article in the Eniyclopedia proteins (qv) nucleic acids (qv) and polysaccharides (see Carbohydrates Microbial polysaccharides). Biopolymers are formed through condensation of monomeric units ie, the corresponding monomers are amino acids (qv), nucleotides, and monosaccharides, for proteins, nucleic acids, and polysaccharides, respectively. The term biopolymers is also used to describe synthetic polymers prepared from the same or similar monomer units as are the natural molecules. [Pg.94]

With remarkable accuracy, Democritus in the fifth century B.C. set the stage for modem chemistry. His atomic theory of matter, which he formulated without experimental verification, still stands, more or less intact, and encapsulates the profound truth that nature s stunning wealth boils down to atoms and molecules. As science uncovers the mysteries of the world around us, we stand ever more in awe of nature s ingenious molecular designs and biological systems nucleic acids, saccharides, proteins, and secondary metabolites are four classes of wondrous molecules that nature synthesizes with remarkable ease, and uses with admirable precision in the assembly and function of living systems. [Pg.1]

As already mentioned, a continual inflow of energy is necessary to maintain the stationary state of a living system. It is mostly chemical energy which is injected into the system, for example by activated amino acids in protein biosynthesis (see Sect. 5.3) or by nucleoside triphosphates in nucleic acid synthesis. Energy flow is always accompanied by entropy production (dS/dt), which is composed of two contributions ... [Pg.241]

Nanoparticle surface modification is of tremendous importance to prevent nanoparticle aggregation prior to injection, decrease the toxicity, and increase the solubility and the biocompatibility in a living system [20]. Imaging studies in mice clearly show that QD surface coatings alter the disposition and pharmacokinetic properties of the nanoparticles. The key factors in surface modifications include the use of proper solvents and chemicals or biomolecules used for the attachment of the drug, targeting ligands, proteins, peptides, nucleic acids etc. for their site-specific biomedical applications. The functionalized or capped nanoparticles should be preferably dispersible in aqueous media. [Pg.237]

In living systems, optically active macromolecules, such as proteins, nucleic acids, and polysaccharides, are extensively involved in life processes. These macromolecules often possess specific conformational and higher... [Pg.157]

Fluorescence is also a powerful tool for investigating the structure and dynamics of matter or living systems at a molecular or supramolecular level. Polymers, solutions of surfactants, solid surfaces, biological membranes, proteins, nucleic acids and living cells are well-known examples of systems in which estimates of local parameters such as polarity, fluidity, order, molecular mobility and electrical potential is possible by means of fluorescent molecules playing the role of probes. The latter can be intrinsic or introduced on purpose. The high sensitivity of fluo-rimetric methods in conjunction with the specificity of the response of probes to their microenvironment contribute towards the success of this approach. Another factor is the ability of probes to provide information on dynamics of fast phenomena and/or the structural parameters of the system under study. [Pg.393]

What are the facts of life One of the most striking is that all known living systems involve the same types of polymers, i.e., three varieties of homochiral biopolymers. That is, each variety is composed of unique molecular building blocks having the same three-dimensional handedness. Thus, with rare exceptions, the proteins found in cells are composed exclusively of the 1-enantiomers of 19 optically active amino acids (Fig. 11.1). Similarly, only D-ribose and 2-deoxy-D-ribose sugars are found in the nucleic acid polymers that make up the RNAs and DNAs, which are essential for protein synthesis in the cell and for the transmission of genetic information from one generation to the next. [Pg.175]

Many years later, Tom Cech and Sidney Altman established that there is a second class of catalytic entities in living systems that are nucleic acid in nature the ribozymes. 1 get around to these in a later chapter. [Pg.106]

The molecules that form the foundation of living systems are often organized into four categories. They are the primary metabolites nucleic acids, proteins, carbohydrates, and lipids. The categories can be grouped together in different ways, based on features that they have in common. For example, nucleic acids, proteins, and polysaccharides are polymeric. Nucleic acids and proteins are further related because they are templated polymers. Other classification systems are also possible.1 Interest in the development of size-expanded versions of biomolecules has grown over the past... [Pg.122]

Plants and animals synthesize a number of polymers (e.g., polysaccharides, proteins, nucleic acids) by reactions that almost always require a catalyst. The catalysts present in living systems are usually proteins and are called enzymes. Reactions catalyzed by enzymes are called enzymatic reactions, polymerizations catalyzed by enzymes are enzymatic polymerizations. Humans benefit from naturally occurring polymers in many ways. Our plant and animal foodstuffs consist of these polymers as well as nonpolymeric materials (e.g., sugar, vitamins, minerals). We use the polysaccharide cellulose (wood) to build homes and other structures and to produce paper. [Pg.180]

Of all the macromolecules present in living systems proteins and nucleic acids are the most significant. Nucleic acid in the form of DNA forms the stored structural and regulatory material for the organism, while proteins and their expression represent the functional form of this information. [Pg.273]

Carbohydrates form the major structural components of the cell walls. The most common form is cellulose which makes up over 30 per cent of the dry weight of wood. Other structural forms are hemicellulose (a mixed polymer of hexose and pentose sugars), pectins and chitin. Apart from contributing to the structure, some polymers also act as energy storage materials in living systems. Glycogen and starch form the major carbohydrate stores of animals and plants, respectively. Carbohydrate structure, like that of nucleic acids and proteins, is complex, and various levels of structure can be identified. [Pg.278]

Fig. 11.1. This figure illustrates the process of selection not by restriction but by fit into the next hierarchy of structures. The suitability is a purely chemical phenomenon and the pinhole plate is an imperfect symbol of fit of fragments into the structures of nucleotides which, in turn, are swept up by polymerization reactions. The aperture at the next station restricts on the basis of suitability of nucleic acids for the development of catalytic units. The aperture symbolizing that differentiating process is larger because there are many ways for nucleic acids to end up in living systems in contrast to the first aperture in barrier 1 that is restrictive to the point that only nucleic acids can cross that threshold. The third aperture is the largest yet because there are many ways to make a living. It is movable because the living units that appear will be sensitive to environmental conditions that can mean failure to life forms which would be quite suitable to exist under different conditions. Fig. 11.1. This figure illustrates the process of selection not by restriction but by fit into the next hierarchy of structures. The suitability is a purely chemical phenomenon and the pinhole plate is an imperfect symbol of fit of fragments into the structures of nucleotides which, in turn, are swept up by polymerization reactions. The aperture at the next station restricts on the basis of suitability of nucleic acids for the development of catalytic units. The aperture symbolizing that differentiating process is larger because there are many ways for nucleic acids to end up in living systems in contrast to the first aperture in barrier 1 that is restrictive to the point that only nucleic acids can cross that threshold. The third aperture is the largest yet because there are many ways to make a living. It is movable because the living units that appear will be sensitive to environmental conditions that can mean failure to life forms which would be quite suitable to exist under different conditions.

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See also in sourсe #XX -- [ Pg.3 , Pg.407 ]

See also in sourсe #XX -- [ Pg.3 , Pg.407 ]




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Living systems

Skill 12.1o-Recognize that inorganic and organic compounds (e.g., water, salt, carbohydrates, lipids, proteins, nucleic acids) are essential to processes within living systems

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