at Related Biological Terms

A technique for evaluation of the molecular mass of a polymer by determination of the extent of sedimentation at which the force exerted upon a macromolecule in a centrifuge is balanced by its diffusion due to Brownian motion. (see also sedimentation-velocity ultracentrifugation)

A fatty acid that is a dietary necessity, e.g. the polyunsaturated fatty acids linoleic acid and linolenic acid.

In cytology, the lightly staining regions of chromosomes that contain less-condensed chromatin and are the regions that are transcribed as RNA. (see also heterochromatin)

The adaptation over evolutionary time of a protein, and its gene, to a novel function; e.g. the transformation of trypsinogen into an antifreeze glycoprotein.

In fluorescence spectroscopy, emission at a longer, fixed, wavelength as a function of the wavelength of the exciting light. (see also emission spectrum)

The use of an expression library constructed from the complete or partial DNA complement of a pathogen to immunize a host without the risk of infection.Barry, M.A., Lai, W.C. and Johnston, SA (1995) Nature (London) 377, 632-635

The blood clotting cascade that is initiated by a tissue factor. (see also intrinsic pathway)

(= fluorescence-based DNA analysis technology (FDAT))

An analysis based on Fourier's theorem that any periodic function may be reduced to a series of sine and cosine terms, each represented by an amplitude and a phase. The transformation is the CASTing of data for a periodic phenomenon into such an alternative form, or the reconstruction of the phenomenon from its mathematical expression, e.g. reconstruction of a molecular model of a compound from an analysis of the X-ray diffraction pattern of its crystal, which is a three-dimensional periodic structure. (see also phase problem) Related tool: molecular biology tools

A transport mechanism that moves compounds or ions down a concentration gradient, and requires no energy; also known as accelerated diffusion or mediated transport. (see also active transport; passive diffusion)