Nucleophilic attack is the attack of an electron rich 
centre upon an electron deficient centre.
a most common example is the nucleophilic attack of the 6-
oh of glucose on the terminal p-o-p bond of atp,forming adp 
plus glucose 6 phosphate.

The quantitative relationship among PH,buffering action of 
amixture of weak acid and its conjugate base and the PKa of 
the weak acid is given by a simple expression called 
HENDERON-HASSELBALCH EQUATION.
The shape of titration curve of any weak acid is expressed 
by Henderson-Hasselbalch equation.This is auseful way of 
restating the expression for the dessociation constant of 
an acid.
For the dessociation of aweak acid HA into H+ and A-,this 
equation can be derived as follows.


Ka=[H+][A-]/[HA]
by rearraning the equation for solving H+

[H+]=Ka[HA]/[A-]

by converting to logarthmic functions

log [H+]=LOG Ka+log[HA]/[A-]

making expression negative

-log[H+]=-logKa-log[HA]/[A-]

SUBSTITUTING ph for -log[H=] and PKa for -logKa
PH=PKa-log[HA]/[A-]
NOW TO REMOVE MINUS SIGN INVERT LAST TERM I.E -LOG[HA]/[A-] 
TO OBTAINHENDERSON-HASSELBALCH EQUATION.
PH=PKa-LOG[A-]/[HA];

bile is slightly alkhaline in nature.
it's ph is  approximately 7.5

In bicarbonate buffer system [HCO3-]/[H2CO3] ratio of 20:1 
is required for the ph of blood plasma to remain 7.4.
if there is any change in the ratio in favour of H2CO3 
acidosis results.


this change can result from a decreasein HCO3 ion  or from 
an increase in H2CO3.

most common forms of acidosis are metabolic or respiratory.

Alkalosis occurs when hco3 ion becomes favoured in the 
bicarbonate or carbonic acid ratio.

metabolic alkalosis occurs when HCO3 ion increases.

respiratory alkalosis occurs is inducedby hyperventilation 
because an excess removal of co2 from the blood results in 
a decrease in H2CO3.

ACIDOSIS: INTERMS OF PH, INCREASE IN THE CONCENTRATION OF H 
IONS\OTHER CATIONS
                    OR 
          DECREASE IN THE CONCENTRATION OF BICARBONATE IONS

       NORMAL RATIO OF BLOOD BICARBONATE BUFFER IS 20:1

ALKALOSIS: DECREASE IN THE CONCENTRATION OFH IONS OR 
INCREASE IN THE CONCENTRATION OF  BICARBONATE 
IONS|SALTS

lavoiser is considered as the father of modern biochemistry.

arther korenburg

carl neuberg

poly saccharides that are composed not only of a mixture of 
simple sugars but also of derivatives of sugars such as 
aminosugars and uronic sugars are called muco poly 
saccharides.

they are gelatinous substances of high molecular weights . 
most of these acts as support material for connective 
tissue or mucous substances of the body.
they consists of disaccharide units in which a uronic acid 
is bound by a glycosidic bond to the c3 of an acetylated 
aminoacid.
eg:hyaluronic acid,chondroitin,keratosulfate etc;

pseudoglobulins and euglobulins are differentiated on the 
basis of solubility behaviour.a pseuduglobulin is soluble 
at very low ionic strength,where as euglobulin remains 
sparingly soluble until the ionic strength isv 
raised.euglobulins remain soluble at the isoelectric 
point,where as pseudoglobulins do not.

The term palindromic dna  is applied to regions of dna in 
which there are inverted repetitions of base sequences with 
twofold symmetry occuring over two strands.

such sequences are selfcomplementary within each of the 
strands and therefore have the potential to form hairpin or 
cruciform structures involving intrastrand base pairing.

an organic molecule which has handedness and hence 
optically active is called chiral molecule.

an organic molecule with carbon attached by four different 
groups are chiral molecule

Acarbon is said to be chiral or assymetric when it is 
attached to four different groups.Their mirror images do 
not superimpose with eachother.

The ossicles are arranged around the mouth and ambulacral
grooves.
The ambulacral grooves are formed of opposite  rod shaped
pieces called ambulacral ossicles arranged in form of "v".

Each ossicle bears a concavity or half pore on its outer and
inner margins.halfpores of adjascent ossicles form an oval
aperture ambulacral pore.
Lateral to these ossicles are present a row of ossicle the
ambulacral ossicle which form edges of grooves.
They bear a group of movable spines mounted on small tubericles.

osphradium is a putative chemosensory organ of aquatic
mollusc.Transmitter-specific sensory cell types like those
discovered in the osphradium are also present as single
neuroepithelial cells in other organs of the mantle complex
in prosobranchs and in the pelecypod Anodonta cygnea.

it is also called as transferrin,is an important 
metalloporotein and constitutes about 30% of the total 
plasma protein.it has a molecular weight of about 90,000 
and is capable of binding 2 atoms of iron peer molecule.it 
facilitates iron transport.

they are inherited and acquired disorders caused by a 
deficiency of an enzyme in the hame biosynthetic 
pathway.about 15% occurs in the liver and remaining in 
erythrocyte precursors. porpyrias are of two types. hepatic 
and erythropoietic types.they are erythropoietic 
porphyria,acute intermittent porphyria,heriditary 
porphyria,cutanea tarda,and lead poisoning.

carnosine - C9H14O2N4 is an optically active crystalline 
dipeptide m.p 260 degrees found in muscle tissue.