DNA strand with another pair of nucleotides. The
bases are one of five compounds—adenine, guanine,
cytosine, thymine, and uracil—that form the genetic
code in DNA and RNA.
basic anhydride A metal oxide that reacts with
water and forms a base.
basicity constant SeeACIDITY CONSTANT.
basicity function SeeACIDITY FUNCTION.
basic oxide Any ionic oxide that dissolves in water
to produce a basic solution.
basic salt A salt that keeps part of the base from
which it is formed. The retained portion can be oxygen
or a hydroxl group.
basic solution A solution in which the hydroxide ion
concentration is higher than the hydronium ion
(hydrated proton) concentration.
bathochromic shift (effect) Shift of a spectral band
to lower frequencies (longer wavelengths) owing to the
influence of substitution or a change in environment. It
is informally referred to as a red shift and is opposite to
HYPSOCHROMIC SHIFT(blue shift).
bathyal zone A region of the seafloor from the shelf
edge (200 m) to the start of the abyssal zone (2,000 m);
zone between the edge of the continental shelf and the
depth at which the water temperature is 4°C.
bauxite An alumina ore that, when smelted, gives up
aluminum. Bauxite usually contains at least 45 percent
aluminum oxide (alumina), and the best grades have a
low silica content. About 4 lb of bauxite are required
to produce 1 lb of aluminum.
Beer-Lambert law The quantitative relationship
between the absorbance of radiant energy, concentration
of the sample solution, and length of the path through
the sample. Named after two scientists, Johann Heinrich
Lambert (1728–77) and August Beer (1825–63), the law
also serves as the basis of spectroscopic instruments that
are being used increasingly in the science curriculum.
Research is still in progress to understand and find
appropriate models for the light absorbance.Bell-Evans-Polanyi principle The linear relation
between ENERGY OF ACTIVATION(Ea) and enthalpy of
reaction (∆Hr) sometimes observed within a series of
closely related reactions.
Ea= A+ B∆Hrbenthic zone The lowermost region of a freshwater
or marine body, pertaining to the bottom terrain of
water bodies. It is below the pelagic zone and above
the abyssal zone by about 9,000 m. Organisms that live
on or in the sediment in these environments are called
benthos.
See alsoOCEANIC ZONE.benzyne 1,2-Didehydrobenzene (the ARYNE derived
from benzene) and its derivatives formed by substitu-
tion. The terms m- and p-benzyne are occasionally used
for 1,3- and 1,4-didehydrobenzene, respectively.Berg, Paul(1926– ) AmericanChemist Paul Berg
was born in Brooklyn, New York, on June 30, 1926, to
Sarah Brodsky and Harry Berg. He attended public
school (Abraham Lincoln) in New York and graduated
early in 1943. Berg studied biochemistry at Pennsylva-
nia State College from 1943 until 1948, receiving a B.S.
in biochemistry. He then attended graduate studies in
biochemistry at Western Reserve University, where he
received his Ph.D. in 1952.
Berg was an assistant professor of microbiology at
Washington University School of Medicine from 1955
to 1959; an associate professor and professor of bio-
chemistry at Stanford University School of Medicine,
Stanford, California, from 1959 to the present; andBerg, Paul 25