Purbesh Mondal, a class XI student at Narayana School in Haldia, conducted a biology project on blood groups. The project discusses the ABO and Rh blood group systems, which are important for blood transfusions. It provides details on antigens and antibodies, the four blood types in the ABO system (A, B, AB, and O), and Rh+ and Rh- blood types. The project concludes that while blood type may influence disease susceptibility, it does not cause disease directly, and increasing knowledge of blood types can help screen those at higher risk.

1. NARAYANA SCHOOL, HALDIA
BIOLOGY PROJECT
Study of Blood Groups
—
Name- Purbesh Mondal
Class- XI
Registration number- 1994111
Session- 2021-22

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Acknowledgement
I am overwhelmed in all humbleness and gratefulness to acknowledge my depth to all
those who have helped me to put these ideas, well above the level of simplicity and into
something concrete.
I would like to express my special thanks giving gratitude to our Biology teacher Jagriti
Ghosh, who helped me out in various ways in making this project as well as our
Principal Ma’am Saheli Ghosh Basu who gave me the golden opportunity to do this
wonderful project, which also helped me in doing a lot of research and I came to know
about so many new things.
Any attempt at any level can’t be satisfactorily completed without the support and
guidance of my parents and friends. I would like to thank them for helping me a lot in
gathering different information, collecting data, and guiding me from time to time in
making this project, despite their busy schedules.

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Content
Sl. no. Topic Page no.
1. Introduction 3
2. Blood Group System 4
3. ABO blood group system 7
4. Rh blood group system 8
5. Blood Transfusion 9
6. Blood Donors and Receivers 10
7. Conclusion 11
8. Sources 12

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Introduction
Blood is a constantly circulating fluid providing the body with nutrition, oxygen, and
waste removal. It is a type of connective tissue. Blood is mostly liquid, with numerous
cells and proteins suspended in it, making blood "thicker" than pure water. The average
person has about 5 liters of blood.
Composition of blood is rather interesting. It consists of erythrocytes, leukocytes and
platelets suspended in plasma along with millions of different molecules with their own
specific roles and functions.
Blood is conducted through blood vessels (arteries and veins). Blood is prevented from
clotting in the blood vessels by their smoothness, and the finely tuned balance of
clotting factors. These blood vessels form a network and is known as the circulatory
system, which also includes the organ Heart.
Even though components of blood are the same for all humans, there are various blood
types. In fact, there are more than 40 blood groups, but all of them are not clinically
significant. The discovery of the ABO blood group created great excitement as until
then, all blood had been assumed to be the same.

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Blood Group System
During the blood transfusion, the two most important group systems examined are the
ABO-system and the Rhesus system.
Karl Landsteiner, an Austrian scientist
discovered the ABO blood group system in the
year 1900. In his experiments, he mixed different
blood types and noted that the plasma from
certain blood types produced agglutinates or
formed clusters which were caused by the
absence of molecules on red blood cells and
resulting in antibodies to defeat that molecule.
He then made a note of the agglutination and
divided the blood types into 4 different groups.
For the discovery of the ABO blood group, he was
awarded the Nobel Prize.
Rh blood group system, system for classifying
blood groups according to the presence or
absence of the Rh(D) antigen, often called the Rh
factor, on the cell membranes of the red blood
cells (erythrocytes). The designation Rh is
derived from the use of the blood of rhesus
monkeys in the basic test for determining the
presence of the Rh antigen in human blood. The
Rh blood group system was discovered in 1940 by
Karl Landsteiner and Alexander Solomon
Wiener.

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The blood grouping system is pivotal in blood transfusion. Our immune system
recognizes another blood type as foreign and attacks it if introduced in the body causing
a transfusion reaction. Any inappropriate match with the Rh and ABO blood types,
causes the most serious and life-threatening transfusion reactions. Therefore, before
blood transfusion, it is suggested to have a blood group checked.
Important terms:-
1. Antigen
In immunology, an antigen is a molecule or molecular structure that can bind to
a specific antibody or T-cell receptor. The presence of antigens in the body may
trigger an immune response. The term antigen originally referred to a substance
that is an antibody generator. Antigens can be proteins, peptides (amino acid
chains), polysaccharides (chains of monosaccharides/simple sugars), lipids, or
nucleic acids.
Antigens are recognized by antigen receptors, including antibodies and T-cell
receptors. Diverse antigen receptors are made by cells of the immune system so
that each cell has a specificity for a single antigen. Upon exposure to an antigen,
only the lymphocytes that recognize that antigen are activated and expanded, a
process known as clonal selection. In most cases, an antibody can only react to
and bind one specific antigen; in some instances, however, antibodies may
cross-react and bind more than one antigen.
The antigen may originate from within the body ("self-protein") or from the
external environment ("non-self"). The immune system identifies and attacks
"non-self" external antigens and usually does not react to self-protein due to
negative selection of T cells in the thymus and B cells in the bone marrow.
Vaccines are examples of antigens in an immunogenic form, which are
intentionally administered to a recipient to induce the memory function of the
adaptive immune system towards antigens of the pathogen invading that
recipient. The vaccine for seasonal influenza is a common example.

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2. Antibody
An antibody, also known as an immunoglobulin, is a large, Y-shaped protein
used by the immune system to identify and neutralize foreign objects such as
pathogenic bacteria and viruses. The antibody recognizes a unique molecule of
the pathogen, called an antigen. Each tip of the "Y" of an antibody contains a
paratope (analogous to a lock) that is specific for one particular epitope
(analogous to a key) on an antigen, allowing these two structures to bind
together with precision. Using this binding mechanism, an antibody can tag a
microbe or an infected cell for attack by other parts of the immune system, or can
neutralize it directly (for example, by blocking a part of a virus that is essential
for its invasion).

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ABO blood Group system
The ABO blood group system consists of 4 types of blood group – A, B, AB, and O and is
mainly based on the antigens and antibodies on red blood cells and in the plasma. Both
antigens and antibodies are protein molecules in which antigens are present on the
surface of Red Blood Cells and antibodies are present in the plasma which is involved in
defending mechanisms.
The basis of ABO grouping is of two antigens- Antigen A and Antigen B. The ABO
grouping system is classified into four types based on the presence or absence of
antigens on the red blood cells surface and plasma antibodies.
● Group A – contains antigen A and antibody B.
● Group B –contains antigen B and antibody A.
● Group AB –contains both A and B antigen and no antibodies (neither A nor B).
● Group O – contains neither A nor B antigen and both antibodies A and B.
The ABO group system is important during blood donation or blood transfusion as
mismatching of blood groups can lead to clumping of red blood cells with various
disorders. It is important for the blood cells to match while transfusing i.e.
donor-recipient compatibility is necessary. For example, a person of blood group A can
receive blood either from group A or O as there are no antibodies for A and O in blood
group A.

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Rh Blood Group System
The Rh blood group system consists of 50 defined blood group antigens. In the Rh
system, the most important antigens are D, C, c, E, and e.
In addition to the ABO blood grouping system, the other prominent one is the Rh blood
group system. About two-thirds of the population contains the third antigen on the
surface of their red blood cells known as Rh factor or Rh(D) antigen; this decides
whether the blood group is positive or negative. If the Rh factor is present, an individual
is rhesus positive (Rh+ve); if an Rh factor is absent the individual is rhesus negative
(Rh-ve) as they produce Rh antibodies. Therefore, compatibility between donor and
individual is crucial in this case as well.
The Rh antigen poses a danger for the Rh-negative person, who lacks the antigen, if
Rh-positive blood is given in transfusion. Adverse effects may not occur the first time
Rh-incompatible blood is given, but the immune system responds to the foreign Rh
antigen by producing anti-Rh antibodies. If Rh-positive blood is given again after the
antibodies form, they will attack the foreign red blood cells, causing them to clump
together, or agglutinate. The resulting hemolysis, or destruction of the red blood cells,
causes serious illness and sometimes death.

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Blood transfusion
A blood transfusion is a routine medical procedure in which donated blood is provided
to you through a narrow tube placed within a vein in your arm. This potentially
life-saving procedure can help replace blood lost due to surgery or injury. A blood
transfusion also can help if an illness prevents your body from making blood or some of
your blood's components correctly. Blood transfusions usually occur without
complications. When complications do occur, they're typically mild.
People receive blood transfusions for many reasons — such as surgery, injury, disease
and bleeding disorders. A transfusion provides the part or parts of blood you need, with
red blood cells being the most commonly transfused. You can also receive whole blood,
which contains all the parts, but whole blood transfusions aren't common. Researchers
are working on developing artificial blood. So far, no good replacement for human blood
is available.

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Blood donors and receivers
Individuals of blood group O- are called as universal donors, whereas individuals
of blood group AB+ are universal recipients.

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Conclusion
Even though many studies have proven the association between ABO blood types and
diseases by describing possible mechanisms, others did not confirm it and making the
exact decision falls into uncertainty due to inconsistent results. Nevertheless, evidences
were collected to make this supposition clear. ABO may influence the risk of different
diseases by different known and unknown mechanisms. It is now clear that ABO blood
types are not the exact cause of diseases, but they can be susceptible and surrender to
disease and health problems. In general, non-O blood types are more susceptible to
diseases than O. It can be useful to increase the knowledge of persons in this aspect
because individuals with high risk blood types could be screened and trained for
modifying their lifestyles, health behavior, and environment and other attempts that
may increase public health. The importance of human blood types can be seen more
clearly in the context of population movement and the persistent combat between
humans and infectious disease. Evidence for selection by infectious diseases at the level
of the ABO and secretor genes is persuasive, but for other blood group antigens,
founder effects appear more likely to account for the distribution of blood group
polymorphisms except for parts of the world in which malaria is endemic. Available data
suggests that survivals from malaria have been the most significant selective force
acting on the blood groups. Moreover, further investigations have to be made
particularly on the molecular level of ABO blood groups and their association with
various diseases.

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Sources
● https://byjus.com/biology/blood-groups/
● https://www.britannica.com/science/Diego-blood-group-system
● https://en.wikipedia.org/wiki/Antibody
● https://en.wikipedia.org/wiki/Antigen
● https://www.britannica.com/science/Rh-blood-group-system
● https://www.webmd.com/heart/anatomy-picture-of-blood

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