Blood Groups and Significance Practice Questions
20 free Blood Groups and Significance practice questions for the NCERT Biology. Tap an option to answer — you get instant feedback, the correct answer, and a detailed explanation for every question.
The ABO blood grouping is based on the presence or absence of two surface antigens on the:
- A Plasma
- B Leucocytes (WBCs)
- C Erythrocytes
- D Platelets (thrombocytes)
Correct answer: Erythrocytes
ABO grouping is determined by specific chemicals called antigens (A and B) present on the surface of the Red Blood Cells (Erythrocytes). These antigens induce an immune response if they are foreign to the recipient.
A person with blood group 'O' has which of the following on their RBC surface and in their plasma?
- A Both A and B antigens on RBCs; no antibodies in plasma
- B No A or B antigens; anti-A and anti-B antibodies in plasma
- C Antigen A; anti-B antibodies
- D Antigen B; anti-A antibodies
Correct answer: No A or B antigens; anti-A and anti-B antibodies in plasma
Blood group O is characterized by the absence of both A and B antigens on the RBC surface. Consequently, the plasma of such individuals contains both anti-A and anti-B antibodies.
Which blood group is considered the 'Universal Donor'?
- A Group AB
- B Group A
- C Group B
- D Group O
Correct answer: Group O
Individuals with blood group O are called universal donors because their RBCs lack A and B surface antigens. This means their blood can be donated to persons with any other blood group without causing an immune reaction.
An individual with blood group 'AB' can receive blood from:
- A Only group AB
- B Only group O
- C Groups A and B only
- D Any blood group
Correct answer: Any blood group
Persons with blood group AB have both A and B antigens on their RBCs but no antibodies in their plasma. Therefore, they can safely receive blood from any group (A, B, AB, or O), making them universal recipients.
The Rh factor is an antigen similar to one present in which of the following animals?
- A Rhesus monkeys
- B Domestic rabbits
- C Common rats
- D Various reptiles
Correct answer: Rhesus monkeys
The Rh antigen is named after the Rhesus monkey, in which it was first discovered. Nearly 80 percent of humans possess this antigen on their RBC surfaces and are termed Rh positive (Rh+).
What will happen if an Rh negative person is exposed to Rh positive blood for the first time?
- A Immediate and severe anaphylactic shock leading to death
- B Production of specific antibodies against Rh antigens
- C Immediate destruction of the person's own RBCs throughout the body
- D No detectable change in the blood composition of that person
Correct answer: Production of specific antibodies against Rh antigens
When an Rh- person is exposed to Rh+ blood, their immune system recognizes the Rh factor as foreign. This triggers the production of specific anti-Rh antibodies in the recipient's plasma.
Erythroblastosis foetalis is a condition that can occur during a pregnancy involving:
- A Rh+ mother and Rh- foetus
- B Rh- mother and Rh+ foetus
- C Rh- mother and Rh- foetus
- D Rh+ mother and Rh+ foetus
Correct answer: Rh- mother and Rh+ foetus
This condition occurs when an Rh- mother carries an Rh+ foetus. During delivery, the mother may be exposed to foetal blood, causing her to develop antibodies that can attack the RBCs of a subsequent Rh+ foetus.
In erythroblastosis foetalis, the antibodies from the mother leak into the foetal blood and cause:
- A Severe anemia and jaundice
- B High blood pressure
- C Excessive blood clotting
- D Rapid growth of the foetus
Correct answer: Severe anemia and jaundice
The anti-Rh antibodies from the mother cross the placenta and destroy the foetal RBCs. This leads to severe anemia and jaundice, which can be fatal to the baby.
How can erythroblastosis foetalis be prevented in a susceptible pregnancy?
- A By administering Rh antigens to the mother before the next pregnancy
- B By giving anti-Rh antibodies to the Rh- mother soon after the first delivery
- C By performing a complete blood transfusion for the Rh- mother after delivery
- D By providing supplemental vitamins and iron to the developing foetus
Correct answer: By giving anti-Rh antibodies to the Rh- mother soon after the first delivery
The condition can be avoided by administering anti-Rh antibodies (RhoGAM) to the Rh- mother immediately after her first Rh+ child's birth. This prevents her immune system from becoming sensitized to the Rh antigen.
Which of the following blood groups contains anti-A antibodies but no anti-B antibodies in the plasma?
- A Group A
- B Group B
- C Group AB
- D Group O
Correct answer: Group B
Individuals with blood group B have the B antigen on their RBCs and naturally occurring anti-A antibodies in their plasma. This prevents them from receiving blood from donors with group A or AB.
During a blood transfusion, what is the most critical factor to check to prevent 'clumping' (agglutination) of RBCs?
- A Total count of white blood cells present in the donor's sample
- B Compatibility of antigens and antibodies
- C Hemoglobin concentration and oxygen-carrying capacity of the recipient
- D Total plasma volume available from the donor
Correct answer: Compatibility of antigens and antibodies
Transfusion compatibility depends on matching the donor's antigens with the recipient's antibodies. If incompatible, the antibodies will attack the donor RBCs, causing them to clump together and lyse.
A person with Rh negative blood can safely donate to:
- A Only to Rh negative recipients
- B Only to Rh positive recipients
- C Both Rh positive and Rh negative recipients
- D No recipient safely, regardless of type
Correct answer: Both Rh positive and Rh negative recipients
Rh- blood lacks the Rh antigen. Therefore, it can be given to both Rh+ and Rh- recipients because there is no antigen present to trigger an immune response in the recipient's body.
If a father is Rh+ and the mother is Rh-, what is the Rh status of their child likely to be (assuming the father is homozygous)?
- A 100% Rh-
- B 50% Rh+ and 50% Rh-
- C 100% Rh+ (all children affected)
- D 25% Rh+ and 75% Rh-
Correct answer: 100% Rh+ (all children affected)
The Rh+ trait is dominant. If a homozygous Rh+ father (DD) and an Rh- mother (dd) have a child, the child will inherit one D allele and one d allele (Dd), resulting in an Rh+ phenotype.
The antibodies for ABO blood groups are found in which component of the blood?
- A Inside the RBCs
- B On the surface of platelets
- C Dissolved in the blood plasma
- D Attached to hemoglobin molecules
Correct answer: Dissolved in the blood plasma
While antigens are located on the surface of the RBCs, the corresponding antibodies (immunoglobulins) are dissolved in the plasma. These antibodies are naturally present from early childhood.
Which blood group does not have any antibodies in the plasma?
- A Blood group A
- B Blood group B
- C Blood group O
- D Blood group AB
Correct answer: Blood group AB
Individuals with blood group AB possess both A and B antigens on their RBCs. Because their body recognises both antigens as 'self', they do not produce anti-A or anti-B antibodies — meaning their plasma is completely free of ABO antibodies.
What percentage of the human population is generally Rh negative?
- A 80%
- B 50%
- C 20%
- D 5%
Correct answer: 20%
Globally, about 80 percent of humans are Rh positive, meaning they have the Rh antigen. The remaining 20 percent lack this antigen and are classified as Rh negative.
Why is blood group AB positive referred to as the 'Universal Recipient' specifically?
- A It lacks all three ABO and Rh antibodies
- B It carries no A, B, or Rh antigens on RBCs
- C It produces all three types of antibodies
- D It has only Anti-Rh antibody in plasma
Correct answer: It lacks all three ABO and Rh antibodies
An AB+ individual has A, B, and Rh antigens on their RBCs. Consequently, their plasma contains no antibodies against these antigens, allowing them to receive any blood type — A, B, O, Rh+ or Rh− — without an immune reaction.
In the ABO system, if a person has group A blood, which antigen-antibody combination do they possess?
- A Antigen A and anti-A antibody
- B Antigen B and anti-A antibody
- C Antigen A and anti-B antibody
- D Antigen B and anti-B antibody
Correct answer: Antigen A and anti-B antibody
A person with blood group A has the 'A' antigen on their RBCs. To prevent self-destruction, they produce antibodies against the 'B' antigen (anti-B) in their plasma.
The clumping of RBCs during an incompatible transfusion is technically known as:
- A Coagulation
- B Agglutination
- C Thrombosis
- D Intravascular fibrinolysis
Correct answer: Agglutination
Agglutination is the specific immune reaction where antibodies bind to antigens on foreign RBC surfaces, causing them to clump together. This is distinct from coagulation, which refers to blood clot formation.
Which statement correctly describes a person with blood group O negative?
- A They can receive blood from anyone
- B They have no antibodies in their plasma
- C They have A, B, and Rh antigens
- D They are the true universal donors
Correct answer: They are the true universal donors
Blood group O- lacks A, B, and Rh antigens. This makes them the true universal donors because their blood will not trigger an immune response regardless of the recipient's ABO or Rh status.