Structure of chlorophyll & haemoglobin

1. Structure of Chlorophyll &
Haemoglobin

2. Structure of Chlorophyll

3. •Chlorophyll is a green color pigment
in green plants and algae.
•It is a magnesium- porphyrin
complex.
•It is a square planar complex with
Mg
2+
the center .
•The magnesium is at the centre of
the modified ring septeon (corrin).
•The modified porphyrin acts as the
ligand.
•It is a naturally occurring chelate
complex of Mg.

5. Structure Of
Hemoglobin

6. •Blood contains red blood corpuscles or
cells .
•About 95% of the dry weight of the red
blood cells is composed of hemoglobin ( or
haemoglobin)
•100mL of the blood of a normal male
contains approximately 15g of
hemoglobin all of which is within the red
blood cells.
•Haemoglobin contains about 0.35% of iron
and thus there are 50mg of Fe per 100mL
blood and 2.5g of iron in the total blood
volume of 5000ml in an adult man.

7. •Haemoglobin is a conjugated protein
having molecular weight of 64,500.
•It is a tetramer in and contains four
identical units which are arranged
roughly in a tetrahedron .
•Each unit contains FOUR identical heme
groups.
• Each hemoglobin molecule has four
heme groups bound to the globin (a
protein) on its surface.
•Fe(II) in hemoglobin is in the high spin
state (Fe
2+
= 3d
6
=t
4
2g
e
2
g
)
•Thus Fe (II) has four unpaired electrons
in hemeglobin molecule.

9. •The structure of haemoglobin is an
octahedral complex of Fe(II).
•The centre of haemoglobin is
occupied by Fe(II) and the four
corners of the square base are
occupied by the four N- atoms of the
heme group.
•One axial position is occupied by N-
atom of histidine while the other
axial positions is occupied by the
H
2
O molecule.

10. Role of hemoglobin in
biological living
systems

11. •Hemoglobin is very sensitive to O
2

and hence readily combines with it
•Thus when we breathe in oxygen,
hemoglobin (Hb) present in our body
combines reversibly with the oxygen
in the lungs to form oxy-hemoglobin
(HbO
2 )
Haemoglobin + O
2
Oxy- hemoglobin
↔
+ H
2
O
(or) Hb + O
2
HbO
↔
2
+ H
2
O

12. •The formation of HbO
2,
is called oxy-
genation of hemoglobin.
•In HbO
2,
Fe is in +3 oxidation state.
•In the formation of HbO
2,
H2o molecules
present at one of the axial positions in
hemoglobin are reversibly replaced by O
2

molecules.
•As the blood runs through the arteries to
the tissues, the oxygen pressure decreases
and oxygen gets bound with the
hemoglobin is set free.

13. •This free oxygen diffuses into the body cells
where it combines with glucose(food) and
oxidizes it into Carbon di oxide and water.
•Thus oxygen is used in the combustion of
food.
C
6
H
12
O
6
+ 6O
2
6CO
→
2
+ 6H
2
0 + 38 ATP

(energy)

14. •The oxidation of glucose to carbon di oxide is an
energy releasing process in which energy in the form
of ATP molecules is produced.
•This energy is utilized by the living organisms to
perform their various metabolic activities, and for
maintaining their body temperature.
•Water produced in the above reaction is retained in
the body while decomposes to give carbon di oxide
and hemoglobin.
•Carbon di oxide is exhaled out and the haemglobin
goes to the lungs for reuse.

15. •The above discussion makes it evident that
the functions of hemoglobin in our body is to
supply oxygen to various parts of the body.
•Thus hemoglobin is an oxygen – carrier.

16. •In the oxygenation of a hemoglobin molecule, a
proton, (H
+
) is also produced.
•

This proton reacts with bicarbonate dissolved in
the blood to liberate carbon di oxide.

HCO
-
3 + H
+ ↔
H
2 CO
3 H
↔
2O + CO
2
CO
2
liberated as above is exhausted out.

19. References
1.Advanced Inorganic Chemistry, Vol II , Satya
Prakash ,G.D.Tuli, S.K.Basu, R.D.Madan.
2.Advanced Inorganic Chemistry, Gurudeep Raj