Nucleic Acid, metabolism, need

Boron is apparently essential for all plants but is needed in only very small amounts. Many plants, especially beans, can tolerate only limited amounts of the element. Its function in plants is still very uncertain but there is considerable evidence that it is involved in cell division, in carbohydrate transport and polymerization, and possibly in nucleic acid metabolism, since a deficiency of the element has been shown to reduce the content of ribonucleic acid (RNA) and desoxyribonucleic acid (DNA). It also seems to play a role in calcium uptake and use in the plant, and in the development and proper functioning of nodules on legumes. 

Goordinated regulation of purine and pyrimidine nucleotide biosynthesis ensures their presence in proportions appropriate for nucleic acid biosynthesis and other metabolic needs. 

Radioactive isotopes provide a very convenient way of monitoring the fate or metabolism of compounds that contain the isotopes. When used in this way, the isotope is described as a tracer and compounds into which the radioactive atom has been introduced are said to be labelled or tagged. The labelled molecules need only comprise a very small proportion of the total amount of the unlabelled radioactive substance because they act in the same way as the non-radioactive substance but can be detected very much more easily. The varied applications of tracers in biochemistry range from studies of metabolism in whole animals or isolated organs to sensitive quantitative analytical techniques, such as radioimmunoassay. Phosphorus-32 is used in work with nucleic acids, particularly in DNA sequencing and hybridization techniques. In these instances the isotope is used as a means of visualizing DNA separations by autoradiographic techniques. 

In addition, as we will learn in the next two chapters, there is still something important missing. In fact, these views refer mostly to the world of low-molecular-weight compounds, namely the bricks for making the house. However, you can have all the low molecular weight compounds in the world, made by hydrothermal vents or by pyrite or by clay or by primitive metabolisms - and you do not make life with that. To make the house, you need at least the macromolecular specific sequences of enzymes and nucleic acids. This leads us nicely into the next two chapters. 

A schematic block diagram of the metabolism of a typical aerobic heterotroph. The block labeled Catabolism represents pathways by which nutrients are converted to small-molecule starting materials for biosynthetic processes. Catabolism also supplies the energy (ATP) and reducing power (NADPH) needed for activities that occur in the second block these compounds shuttle between the two boxes. The block labeled Biosynthesis represents the synthesis of low- to medium-molecular-weight components of the cell as well as the synthesis of proteins, nucleic acids, lipids, and carbohydrates and the assembly of membranes, organelles, and the other structures of the cell. 

The study of metabolism is a study of energy where does the energy to create complex biomolecules — lipids, proteins, and nucleic acids — come from Where does the energy to enable a living organism to do mechanical work come from How is energy stored in the cell and made available when and where it needs to be ... 

In biological systems, proteins and nucleic acids perform two major roles metabolism and conversion of materials and the storage and transmission of genetic information. Proteins are synthesized according to programs written in DNA, while nucleic acid replication and repair both require protein functionality. Proteins and nucleic acids needs each other - they are interdependent. 

---