Molecular biology, terms defined

MOLECULAR BIOLOGY. A self-defining term—the study of biological substances and phenomena at the molecular level. 

The possible information contained in a biomolecule is termed its complexity. In molecular biology and biochemistry, complexity is defined as the number of different sequences in a population of macromolecules. Even a relatively small polymer has an enormous number of potential sequences. DNA, for example, is built from only four monomers A, C, G, and T. If each of these monomers is linked with every other one, these 4 monomers now produce/contain 16... 

Biochip is a broad term indicating the use of microchip technology in molecular biology and can be defined as arrays of selected biomolecules immobilized on a surface. Most of the biochips use nucleic acids as information molecules but protein biochips are also proving to be useful. The basics of protein biochip construction are similar to those of DNA chip as the glass or the plastic surface is dotted with an array of molecules (these... 

Enzymes are excellent catalysts for two reasons great specificity and high turnover rates. With but few exceptions, all reac tions in biological systems are catalyzed by enzymes, and each enzyme usually catalyzes only one reaction. For most of the important enzymes and other proteins, the amino-acid sequences and three-dimensional structures have been determined. When the molecular struc ture of an enzyme is known, a precise molecular weight could be used to state concentration in molar units. However, the amount is usually expressed in terms of catalytic activity because some of the enzyme may be denatured or otherwise inactive. An international unit (lU) of an enzyme is defined as the amount capable of producing one micromole of its reaction product in one minute under its optimal (or some defined) reaction conditions. Specific activity, the activity per unit mass, is an index of enzyme purity. 

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