Biology Glossary - W

W

 Tryptophan

 see amino acids

W forms

 see v–w transition.

W-reactivation

 weigle reactivation.

Wagatsuma agar

A medium containing human or horse RBCs added to a basal medium of yeast extract, peptone, NaCl (7%), Dmannitol, crystal violet, and agar.

wakame

see undaria.

Waldhof fermenter

a type of fermenter in which aeration and agitation are provided by a hollow-bladed wheel-type impeller.

walking (mol. biol.)

See chromosome walking.

wall-forming body

 A granule, present in a coccidian macrogamete, which subsequently contributes to the structure of the oocyst wall.

Wallal subgroup

 see orbivirus.

Wallemia

 A genus of osmophilic fungi which form reddish brown mycelial growth e.g. on jams and salted fish; chains of spores develop acropetally. W. sebi may be related to the

Filobasidiaceae.

Wangiella

A genus of fungi of the class HYPHOMYCETES.W. dermatitidis (sometimes called ‘Hormiscium dermatitidis’, ‘Hormodendrum dermatitidis’ or ‘Phialophora dermatitidis’)

can grow saprotrophically in e.g. soil, but it can also act as a dermotropic and/or neurotropic pathogen in man ; dark, budding, yeast-like cells are formed in culture, but in tissues the organism occurs predominantly in the form of dark hyphae. Non-septate, spherical to ovoid, smooth conidia are produced from flask-shaped to cylindrical, smooth, brown phialides which lack collarettes .

Warburg–Dickens pathway

Syn. hexose monophosphate pathway.

Warburg effect  

The inhibition of co2 fixation and o2 evolution during oxygenic photosynthesis by the presence of high levels of o2; the effect is due at least in part to the competitive inhibition of the carboxylase function of ribulose 1,5-bisphosphate carboxylase–oxygenase by O₂ and an increased rate of photorespiration.

water cycle

Worldwide circulation of water molecules, powered by the sun. Water evaporates from oceans, lakes, rivers, and, in smaller amounts, soil surfaces and bodies of organisms; water returns to the Earth in the form of rain and snow. Of the water falling on land, some flows into rivers that pour water back into the oceans and some percolates down through the soil until it reaches a zone where all pores and cracks in the rock are filled with water (groundwater); the deep groundwater eventually reaches the oceans, completing the cycle.

water potential

The physical property predicting the direction in which water will flow, governed by solute concentration and applied pressure.

water vascular system

A network of hydraulic canals unique to echinoderms that branches into extensions called tube feet, which function in locomotion, feeding, and gas exchange.

wavelength

The distance between crests of waves, such as those of the electromagnetic spectrum.

wild type

An individual with the normal phenotype.

wobble

A violation of the base-pairing rules in that third nucleotide (5' end) of a tRNA anticodon can form hydrogen bonds with more than one kind of base in the third position (3' end) of a codon.

worker

A member of the nonreproductive laboring caste of social insects.