Blood Typing

Question 1

The ABO blood group system is a way of classifying blood based on the

Answer 1

presence or absence of two antigens(A,B) on the RBC
surface
Blood Grouping: Determined by antigens on surface of RBCs

Question 2

ABO The gene is located on the …….. arm of the chromosome…..

ABO antigens located on

Answer 2

long 9 ( 9q34)

lymphocytes, platelets, tissue cells, bone marrow and solid
organs. RBCs

Question 3

The A and B alleles each encode a …………………. that catalyzes the final step in the synthesis of the A and B antigen,respectively.
The O allele encodes an inactive ……………. that leaves the ABO antigen precursor (the antigen) unmodified.
That is, an enzyme that modifies the …….. content of the red blood cell antigens.

Answer 3

glycosyltransferase (A and
B transferases)

glycosyltransferase

carbohydrate

Question 4

• Blood group antigens are “…”,

Answer 4

codominant

• The three alleles of the gene are represented by the symbols IA, IB & i°
• The IA & IB alleles are co-dominant - both are
dominant to the i allele

Question 5

Individual’s will form immune antibodies to ABO blood group antigens they do not possess.
Called

Answer 5

Landsteiner’s Rule

Question 6

Why do individuals produce antibodies to antigens they do not have?

Answer 6

•Substances are present in nature which are so similar to
blood group antigens like some other plants and microorganisms

Question 7

…. is the predominant antibody in Group A and Group B individuals( Anti-A, Anti-B)

……(with some IgM) is the predominant antibody in Group O individuals Anti-A,B (with some anti-A and anti-B)

Answer 7

IgM

IgG

Question 8

People with TYPE O blood are
called …………….
because …….

People with TYPE AB blood are
called …………..because….

Answer 8

Universal Donors, they can give blood to any blood type.

Universal Recipients, because
they can receive any blood type.

Question 9

• Rh antigens are

Answer 9

transmembrane proteins
with loops exposed at the surface of red blood cells.
They appear to be used for the transport of carbon dioxide and/or ammonia across the plasma membrane…

Question 10

Rh Genetics: The genes that control the system are autosomal codominant located

Answer 10

on the short arm
of chromosome 1

Question 11

Why is an Rh incompatibility so dangerous when ABO incompatibility is not during
pregnancy?

Answer 11

• Most anti-A or anti-B antibodies are of the IgM
class (large molecules) and these do not cross the
placenta.

• In fact, an Rh-/type O mother carrying an
Rh+/type A, B, or AB foetus is resistant to
sensitisation to the Rh antigen.
1=1.20