enzyme work but was not allowed to accept it, since he
was living under the Hitler regime. He later discovered
how the conversion of light energy to chemical energy
is activated in photosynthesis. He even showed the car-
cinogenic nature of food additives and cigarette smoke
and demonstrated how cancer cells are destroyed by
radiation during the 1930s.
Warburg is the author of New Methods of Cell
Physiology(1962). He died on August 1, 1970.
water Two atoms of hydrogen and one atom of
oxygen.
water cycle The process by which water is transpired
and evaporated from the land and water, condensed in
the clouds, and precipitated out onto the earth once
again to replenish the bodies of water on the Earth.
water equivalent The amount of water that would
absorb the same amount of heat as the calorimeter per
degree of temperature increase.
water of crystallization Water that is in chemical
combination with a crystal. While it is necessary for the
maintenance of crystalline properties, it is capable of
being removed by sufficient heat; water that is present
in hydrated compounds.
water potential Direction of water flow based on
solute concentration and pressure. OSMOSISis an exam-
ple, which is the DIFFUSIONof water across a semiper-
meable barrier such as a cell membrane, from high
water potential to lower water potential.
It is also a measure of the moisture stress in plants
or soil, measured in megapascals. A more negative value
indicates greater moisture stress. Soils with no moisture
stress have a water potential of 0 to –1 mPa. Two meth-
ods of measuring soil water potential are the heat-dissi-
pation method or the electrical-resistance method.
water table The level below the Earth’s surface at
which the ground becomes saturated with water; usu-
ally mimics the surface contour and is set where hydro-
static pressure equals atmospheric pressure.water vapor Water present in the atmosphere in
gaseous form. Water vapor is an important part of the
natural GREENHOUSE EFFECT. While humans are not sig-
nificantly increasing its concentration, it contributes to
the enhanced greenhouse effect because the warming
influence of greenhouse gases leads to a positive water
vapor feedback. In addition to its role as a natural
greenhouse gas, water vapor plays an important role in
regulating the temperature of the planet because clouds
form when excess water vapor in the atmosphere con-
denses to form ice and water droplets and precipitation.Watson-Crick model A DNA molecule consisting of
two polynucleotide strands coiled around each other in
a helical “twisted ladder” structure.wave function A function of the coordinates of an
electron’s position in three-dimensional space that
describes the properties of the electron.wavelength The physical distance between points of
a corresponding phase of two consecutive cycles of a
wave.weak acid/base A BRONSTED ACID that only par-
tially dissociates into hydrogen ions and anions in solu-
tion. A weak BASEonly partially reacts to form ions in
solution, e.g., ammonia.weak electrolyte Any substance that poorly con-
ducts electricity in an aqueous solution; gives a low-
percentage yield of ions when dissolved in water.wetting agent SURFACTANTfor use in spray formula-
tions to assist dispersion of a powder in the diluent or
spreading of spray droplets on surfaces. A surface-
active agent that promotes wetting by decreasing the
cohesion within a liquid (i.e., reduces the SURFACE TEN-280 water