ABO EXAMINATION TEST Questions with Correct Answers
(Grade A+)
Question 1: Who discovered the ABO blood group system?
Answer: Karl Landsteiner discovered the ABO blood group system in 1900.
Question 2: What does Landsteiner's rule state?
Answer: Landsteiner's rule states that healthy individuals possess ABO antibodies to the ABO blood group
antigens absent from their RBCs.
Question 3: Where can ABO antigens be found?
Answer: ABO antigens can be located in cells, body fluids, and secretions.
Question 4: What are the three genes that influence ABO antigens?
Answer: The ABO, H, and Se genes influence the occurrence and location of ABO antigens.
Question 5: What is the role of the H gene?
Answer: The H gene controls the presence or absence of ABH antigens on the RBC membrane.
Question 6: What is the significance of the Se gene?
Answer: The Se gene influences the presence or absence of ABH antigens in secretions.
Question 7: What are type 1 and type 2 oligosaccharide structures?
Answer: Type 1 and type 2 oligosaccharide structures are different configurations of sugar chains found in
blood group antigens.
Question 8: What is the H antigen's relationship to ABO antigens?
Answer: The H antigen is the foundation for the A and/or B antigens.
Question 9: What enzyme does the H gene code for?
Answer: The H gene codes for a glucosyltransferase enzyme that transfers L-fucose to the oligosaccharide
chain.
Question 10: What are the immunodominant sugars for A and B antigens?
Answer: The A gene adds N-acetylgalactosamine, while the B gene adds D-galactose to the H antigen.
Page 1
, Question 11: What are the main subgroups of the A blood type?
Answer: The two main subgroups of A are A1 and A2.
Question 12: How can A1 and A2 subgroups be distinguished?
Answer: A1 and A2 can be distinguished using the lectin Dolichos biflorus; A1 agglutinates, while A2 does
not.
Question 13: What is the Bombay phenotype?
Answer: The Bombay phenotype is a genetic condition where individuals lack the H antigen (hh).
Question 14: What are ABO antibodies?
Answer: ABO antibodies are naturally occurring, non-RBC stimulated antibodies that result from exposure
to similar antigens in the environment.
Question 15: When do ABO antibodies typically develop?
Answer: ABO antibodies may not be detected until 2-6 months of age.
Question 16: What is the clinical significance of identifying blood type subgroups?
Answer: Identifying blood type subgroups is crucial to avoid transfusion reactions caused by mismatched
blood.
Question 17: What are the possible ABO genotypes for a given ABO phenotype?
Answer:
1. Possible ABO genotypes include AA
2. AO
3. BB
4. BO
5. AB
6. and OO for the respective phenotypes.
Question 18: What is the universal donor blood type?
Answer: The universal donor blood type is O, as it lacks A and B antigens.
Question 19: What is the universal recipient blood type?
Answer: The universal recipient blood type is AB, as it has both A and B antigens.
Page 2
(Grade A+)
Question 1: Who discovered the ABO blood group system?
Answer: Karl Landsteiner discovered the ABO blood group system in 1900.
Question 2: What does Landsteiner's rule state?
Answer: Landsteiner's rule states that healthy individuals possess ABO antibodies to the ABO blood group
antigens absent from their RBCs.
Question 3: Where can ABO antigens be found?
Answer: ABO antigens can be located in cells, body fluids, and secretions.
Question 4: What are the three genes that influence ABO antigens?
Answer: The ABO, H, and Se genes influence the occurrence and location of ABO antigens.
Question 5: What is the role of the H gene?
Answer: The H gene controls the presence or absence of ABH antigens on the RBC membrane.
Question 6: What is the significance of the Se gene?
Answer: The Se gene influences the presence or absence of ABH antigens in secretions.
Question 7: What are type 1 and type 2 oligosaccharide structures?
Answer: Type 1 and type 2 oligosaccharide structures are different configurations of sugar chains found in
blood group antigens.
Question 8: What is the H antigen's relationship to ABO antigens?
Answer: The H antigen is the foundation for the A and/or B antigens.
Question 9: What enzyme does the H gene code for?
Answer: The H gene codes for a glucosyltransferase enzyme that transfers L-fucose to the oligosaccharide
chain.
Question 10: What are the immunodominant sugars for A and B antigens?
Answer: The A gene adds N-acetylgalactosamine, while the B gene adds D-galactose to the H antigen.
Page 1
, Question 11: What are the main subgroups of the A blood type?
Answer: The two main subgroups of A are A1 and A2.
Question 12: How can A1 and A2 subgroups be distinguished?
Answer: A1 and A2 can be distinguished using the lectin Dolichos biflorus; A1 agglutinates, while A2 does
not.
Question 13: What is the Bombay phenotype?
Answer: The Bombay phenotype is a genetic condition where individuals lack the H antigen (hh).
Question 14: What are ABO antibodies?
Answer: ABO antibodies are naturally occurring, non-RBC stimulated antibodies that result from exposure
to similar antigens in the environment.
Question 15: When do ABO antibodies typically develop?
Answer: ABO antibodies may not be detected until 2-6 months of age.
Question 16: What is the clinical significance of identifying blood type subgroups?
Answer: Identifying blood type subgroups is crucial to avoid transfusion reactions caused by mismatched
blood.
Question 17: What are the possible ABO genotypes for a given ABO phenotype?
Answer:
1. Possible ABO genotypes include AA
2. AO
3. BB
4. BO
5. AB
6. and OO for the respective phenotypes.
Question 18: What is the universal donor blood type?
Answer: The universal donor blood type is O, as it lacks A and B antigens.
Question 19: What is the universal recipient blood type?
Answer: The universal recipient blood type is AB, as it has both A and B antigens.
Page 2
