blood group study in bio

1. Blood Groups
-By Srishti Goel VIII D

2. BLOOD GROUPS
Red blood cells (rhethrocytes) have certain proteins on their surface, called antigens. There are two types of
antigens – A and B. On the bases of the presence or absence of these antigens, four types of blood groups have
been identified – A, B, AB, and O. Antibodies are a type of Y shape proteins present in the body plasma.
Antibodies are also either ‘A’ or ‘B’ depending on the type of antigen present.
This chart informs us that if the RBCs of a person consists of
antigen A and antibodies B, then the blood group is A. if the
RBCs of a person consists of antigen B and antibodies A, then
the blood group is B. If both antigens are present and no
antibodies, then the blood group is AB. If there are no antigens
and both antibodies are present, then the blood group is O.

3. BLOODGROUP COMPATIBILITY
During blood transfusion (transfer of blood from one person to another), the blood of the donor (person who donates the
blood) is matched with that of the recipient (person who receives the blood). This is known as blood group compatibility. If
the blood group is incompatible, the antigens of the donor’s blood are attacked by the antibodies of the recipients blood.
This results in serious illness or even death of the recipient. The following table shows the matching of blood groups in case
of a blood transfusion.
Universal Recipient: A person with the blood group
AB can receive blood from all other blood groups
Universal Donor: A person with the blood group O
can donate blood to all other blood groups

4. RHESUS FACTOR
The Rhesus (RH) Factor determines the compatibility of blood transfusion. A person is called Rh – positive or Rh – negative
depending upon the presence or absence of the Rh factor. If the blood of an Rh – positive donor is transfused into the Rh
– negative recipient, they will develop antibodies against the Rh factor since Rh – negative people do not have an
antibody in the plasma against the Rh factor. Repeated transfusion of Rh – positive blood to such a recipient will have
serious illness and result to death.