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S.D. or s.d.: See standard deviation.
S.E. or s.e.: See standard error of the mean.
salt linkage: the ionic bond between fixed ions of opposite
charges on proteins due to Coulombic interaction.
salt-linkage hypothesis: a hypothesis offered by G.N. Ling in
1952 to account for the failure to demonstrate selective adsorption of K+,
Na+ in isolated proteins. This hypothesis was confirmed by
Ling and Zhang in 1984.114
saltatory route: a mode of migration of ions in fixed charge
systems in which the ion penetrates the cell through the
polarized-oriented surface water between fixed sites without undergoing
an adsorption-desorption process.
sarcode: the name given by Felix Dujardin to what was later
called protoplasm.
sarcomere: the basic unit of the contractile machine in striated
muscle A longitudinally oriented sequence of sarcomeres makes up a
myofibril. A bundle of myofibrils, in turn, makes up the substance of a
muscle fiber or cell.
sartorius muscle: a thin, flat muscle extending from the pubis to
the side of the knee. In the frog, the sartorius muscle contains about
1000 single muscle fibers, each running parallel to one another all the
way from one end of the muscle to the other end.
satellite peaks: Due to the nuclear Zeeman effect, the NMR peak
of a nuclide like Na23 with non-spherical distribution of
nuclear charge splits into three peaks, a tall one in the middle and two
flat ones one on each side. These side ones are called satellite peaks.
saturated hydrocarbon: a hydrocarbon molecule with neither free
valence, nor double bond nor triple bond.
scalar quantity: a quantity that has magnitude but no direction.
(The opposite is vector.)
Schwann's cell theory: the theory offered in 1839 by Theodor
Schwann that living cells are the basic units of all living matter.
scintillation counter: See
γ-scintillation counter.
SDS: See sodium dodecyl sulfate.
second order quadrupole broadening: In an exaggerated quadrupole
splitting of NMR signal, the center peak falls below the theoretically
expected value and the phenomenon is then known as second order
quadrupole broadening.
secondary structure of protein: the folding (or non-folding)
pattern of a protein.
semipermeability: a name originally introduced by van't Hoff
describing the (assumed) properties of membranes that allow only the
passage of water but not the solute dissolved in the water As time went
by, a much looser definition became accepted in which quantitatively
different permeability toward water and solutes are also considered as
indicative of semipermeability.
semipermeable membrane: Now taken more to mean that a membrane is
semipermeable if some constituent of a given solution passes through
rapidly while others do not. (See semipermeability.)
Sephadex column: a column packed with beads of cross-linked
dextran—high molecular weight polysaccharides containing exclusively
D-glucose or dextrose monomeric units—used in gel filtration, desalting
and in concentrating protein solutions.
serine: a common a-amino acid found in most protein hydrolysates When
incorporated into a protein, a serine residue offers a hydroxyl group on
a short side chain.
serosal membrane: the membrane of a bifacial epithelial cells
like that of the intestine which faces the side opposite to that of the
intestinal lumen.
SH group: sulfhydryl group, found in proteins on cysteinyl
residues.
"shell of high probability of association": Ants are attracted to
a lump of sugar lying on the ground. If one draws imaginary concentric
circles around the sugar lump, and take successive photos of the sugar
lump and visiting insects, you will find that the circular band
immediately next to the sugar lump will have more visitor-ants recorded
than the next band, and so on. Thus the circular band nearest to the
sugar may be called the "band of high probability of visits." If we now
move to a three-dimensional world of atoms and ions, replace the sugar
lump with an attractive fixed oxyacid anion and the visiting ants with
free cations like K+. draw imaginary concentric spherical
shells around the fixed anion, and again take photos repeatedly, then
one will find that the shell closest to the fixed anions will have the
high probability of receiving visiting K+, the next shell
less and so on. The closest shell is what is called the "shell of high
probability of association."
short-range attributes: properties which cannot be perceived
without direct contact and thus opposite to long-range attributes which
can be perceived from a distance.
short-range influence: influence which can only reach sites
close-by.
sigmoid curve: an S-shaped curve.
sigmoidity: being S-shaped.
silicone rubber: rubber made from silicone elastomers noted for
its retention of flexibility, resilience and tensile strength.
silicone rubber gasket: packing of silicone rubber that makes a
frog muscle in an EMOC preparation fluid-tight.
silver electrode: an electrode when used in conjunction with a
reference electrode and a voltage-measuring instrument or pH meter can
determine the silver ion concentration (or more accurately, activity) in
a solution, just as a pH electrode can measure the activity of H+
in a solution.
silver grains: Photographic film contains light-sensitive silver
salt as part of an emulsin also containing gelatin. On exposure to
light, metallic silver grains are formed at the location of light
exposure and "paints" the darker touches of the image.
sine qua non: an absolutely indispensable or essential
thing.
Singer-Nicolson fluid mosaic membrane theory: a theory of cell
membrane structure offered by S.J. Singer and G.L. Nicolson in 1960 in
which a phospholipid bilayer forms the continuous phase of the membrane
with islands of protein molecules fully or partly submerged.
single fiber sucrose space method: A method introduced by G. N.
Ling, S. Will and P. Shannon to measure the size of the extracellular
space in frog muscle by quantitative comparison of the concentration of
radioactively labeled sucrose in single muscle fibers which have no
extracellular space and whole muscles which do.
size rule: the q-value of a solute in cell water and water in
model systems varies inversely with the molar volume or size of the
solute.
Sloan-Kettering Institute: Memorial Sloan-Kettering Cancer Center
located at 1275 York Ave. in Manhattan, New York.
SO42-: the sulfate anion.
sodium azide: NaN3, a poison.
sodium channel, Na channel: a hypothetical pore-like structure in
the cell membrane based on the membrane pump theory It is supposed to be
closed when the cell is at rest but opens momentarily during activity
when it would allow only Na+ ion to go through but nothing
else.
sodium citrate: ÑáÍ5O7Na3·3H2O,
the sodium salt of citric acid, to which citrus fruits owe their
acidity.
sodium dodecylsulfate: a long-chain anionic detergent.
sodium iodoacetate: the sodium salt of iodoacetic acid, a
metabolic poison.
sodium pump: a hypothetical mechanism located in the cell
membrane, which ceaselessly pumps Na+ out of the cell at the
expense of metabolic energy and in spite of constant inward diffusion so
that a suitable low concentration of this ion is maintained. {See
Chapter 12 and also [15.4].}
sodium pump hypothesis: a hypothesis for the existence and
function of the sodium pump.
sol: liquid colloidal system as defined by Thomas Graham.
soleus muscle: a broad, flat muscle of the calf of the leg,
situated under the gastrocnemius muscle.
solute: a dissolved substance
Solution 731: a special frog Ringer's solution containing
vitamins, free amino acids and other nutrients as well as antibiotics in
which isolated frog muscle could survive as long as 9 days at room
temperature. See Ref. 381.
solvate: a complex of an ion and solvent molecules.
solvency: the quality or state of being able to dissolve.
soma: all of an organism except the germ cells.
sorb: to take up and hold by either adsorption or absorption.
sorbitol: one of the six-carbon sugar alcohols (hexitols), also
known as D-sorbitol or D-glucitol. It is one of the most wide-spread
naturally occurring polyols found exclusively in plants.
sorption: the process, or state of being sorbed.
sorption theory: A theory of solute distribution in living cells
presented formally and in depth in book form by A.S.Troshin in 195891
(possibly in 195690), in which a solute may exist as free solute in cell
water and adsorbed or otherwise complexed to cell proteins. According to
Troshin himself, basic ideas of this theory were introduced earlier by
M. Fischer, W.W. Lepeschkin, D. Nasonov, and others. (See Chapter 7 for
details.)
spatial fixation: the act of holding motionless at a location in
space.
spin quantum number: The rotation of an electron along its axis
is called spin and as such contributes to the total angular momentum.
The contribution is supposed to be quantized. The spin quantum number of
electrons represented by s, can have only two alternative values, viz.,
+1/2 and -1/2 (in units of angular momentum, h/2π where h is the Planck
constant equal to 6.625
× 10-27 erg second) with one spin rotating in
one direction and the other in the opposite direction. In the case of
atomic nuclei, the nuclear spin quantum number is zero or an odd or even
multiple of 1/2. As a general rule, elements of even atomic weight have
zero nuclear spin (with the exception of deuterium and nitrogen).
Hydrogen nucleus has spin quantum number of' 1/2. Na23, 3/2.
spinal cord: the longitudinal cord of nervous tissue extending from the
brain along the back inside the cavity within the column of vertebrae
called the spinal canal.
"sponge protein": nickname of the intracellular protein(s) in bifacial
epithelial cells, which sops up ions and/or other transported solutes
and discharges them in cycles as part of the hypothetical mechanism for
true active transport according to the AI Hypothesis.
squid axon, squid giant axon: Giant nerve fiber measuring some 400 to
800
μ in diameter can be dissected from North Atlantic squids (Loligo)
and is a very useful nerve preparation for the investigations of the
nerve impulses and their underlying mechanisms. Similar giant axons are
obtainable from cuttlefish (Sepia). Chilean squid axons may have
diameters as large as 1.5 mm.
standard deviation, S.D. or s.d.: a statistical parameter to measure the
degree of scattering or dispersion in a population of measurements or
values It is equal to the quadratic means of the deviations of values
from the arithmetic mean, or put differently, it equals the square root
of the sum of the squares of the deviations from the arithmetic mean
divided by the degree of freedom or sample size.
standard error of the means, S.E. or s.e.: a statistical parameter
measuring dispersion and equal to the standard deviation of the sample
divided by the square root of the sample size.
standard free energy of adsorption: In the context of this document, the
standard free energy of adsorption (ΔF°) refers to the free energy
change associated with the (close-contact) adsorption of an ion,
molecule or other solute on an adsorption site. And it is related to the
equilibrium adsorption constant, K, by the relation:
ΔF° = - RT ln K,
where R and Ò are the gas constant and absolute temperature
respectively. (See van't Hoff equation for the historical derivation of
this equation.)
s.andard free energy of solute distribution,
ΔF°: The standard free
energy change (ΔF°) in the distribution of a solute between two
contiguous but largely immiscible phases is described by the equation:
ΔF° = - RT ln q (which can be derived from van't Hoff equation for
chemical reactions), where R and Ò are the gas constant and absolute
temperature respectively, q is the true equilibrium distribution
coefficient of the solute.
standing Ê potential: a concept introduced in the Hodgkin-Huxley theory
of action potential It refers to the steady or standing potential
generated by the much higher (assumed free) K+ concentration within
living cells than that in the free K+ concentration in the bathing
medium. {For evidence intracellular K+ is in fact not free, see
[10.2].}
standing Na potential: a concept introduced in the Hodgkin-Huxley theory
of action potential It refers to the steady or standing potential
generated by the much higher free Na+ concentration in the surrounding
medium than the much lower Na+ concentration in (the assumed free) cell
water. {For evidence that cell water is not free, see Chap. 11}
static: of or relating to body at rest and exerting influence without
motion.
static structure: of or relating to structure at rest.
statistical mechanics: a branch of mechanics dealing with the
application of the principle of statistics to the mechanism of a system
consisting of a large number of parts having motions that differ by
small steps over a large range.
steady state: a condition of a system where no changes are observable in
a particular parameter due to the fact that any process occurring in one
direction is exactly balanced by an equivalent process in the opposite
direction The shape of the flame of a steadily burning candle represent
such a steady state. In its common usage, a steady state is maintained
by a continual supply of energy and in this way it differs from an
equilibrium state.
Stentor: any of a widely distributed Genus (Stentor) of ciliated
protozoa that have a trumpet-shaped body attached to the substrate at
the small end and with the mouth at the large end.
steroid: any of the numerous compounds containing the ring system of
sterols.
stoichiometric: of, or relating to, quantitative chemical properties and
composition, esp. as a factor in chemical or physical change.
straight-line distribution curve, significance of: See rectilinear
distribution curve, significance of.
striated muscle: muscle tissue that is marked by transverse dark and
light bands and under voluntary control (in contrast to smooth muscle
which does not show striation nor under voluntary control).
strontium: a malleable bivalent metal belonging to the alkali earths,
its ion represented as Sr2+.
strychnine (sulfate): alkaloid present in seeds of Strychnof nux vomica
and other species of Strychnos genus; a nerve poison, causing intense
convulsion.
subcellular particles (organelles): specialized structures in living
cells like mitochondria.
substrate: a substance acted upon (as by an enzyme); the base on which
an organism lives; an underlying support.
sucrose, cane sugar: a sweet-tasting disaccharide from sugar canes and
beets When hydrolyzed, it yields an equimolar mixture of D-glucose and
D-fructose.
sulfonate group: SO3-, the univalent anionic group of the dissociated sulfonic acid, SO3H.
superconducting magnet: In certain metals (e.g.,
niobium-titanium), electric resistance drops to zero when the
temperature is brought to near absolute zero. A superconducting magnet
is made from coils of wire of these metals, where rapid circular
electric current produces strong magnetic field while the coils are kept
at liquid helium temperature (-268.9°).
supercool: to cool below the freezing point without crystallization or
solidification.
surface adsorption theory, SA theory: older name of the theory of
cellular electrical potential according to the association-induction
hypothesis, now known as the close-contact surface-adsorption (CSA)
theory.
surface component of the polarization energy (Us): the portion of the
water-to-water interaction energy in polarized and oriented water which
arises from the enhanced interaction of a solute molecules with the
immediately surrounding water molecules.
surface-limited diffusion: If the slowest step in a diffusion process
from one phase (say a solid) to another phase (say a liquid) is across
the boundary between the phases, the process is surface-limited.
surrogate ion: an ion that serves as a substitute for another ion.
swelling and shrinkage: increasing and decreasing of the volume of a
body, usually as a result of the gain or loss of its water content.
swelling water: water in a swollen tissue, cell or colloid.
switch protein: nickname of a hypothetical protein, which turns on or
off a physiological process.
switching: making a shift or exchange.
synapse: the point at which a nerve impulse passes from one neuron to
another.
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