This set of Biology Multiple Choice Questions & Answers (MCQs) focuses on “Body Fluids – Blood – 2”.
1. Which of these blood groups do not have a surface antigen?
Explanation: In the ABO blood grouping system, the blood group is determined by antigenic determinants present on the surface of the red blood cell. ‘O’ blood group does not have any surface antigen.
2. What happens when blood groups are not compatible during blood transfusion?
a) Formation of eosinophils
b) Only neutrophils are destroyed
c) Destruction of RBCs
d) Formation of basophils
Explanation: A successful blood transfusion takes place only when the blood groups of the donor and the recipient are compatible. When the blood groups are not compatible, it results in the destruction of RBCs.
3. Persons having which blood group are known as universal donors?
Explanation: People having the blood group ‘O’ are said to be universal donors. This is because they lack antigens on the surface of their RBCs and hence, their blood can be used to carry out blood transfusions.
4. Which of these are present in the plasma of a person having ‘O’ blood group?
a) Anti-A and anti-B
d) Antibodies are absent
Explanation: For people having ‘O’ blood group, their red blood cells do not have any surface antigens. However, the antibodies anti-A and anti-B are present in the plasma of people having this blood group.
5. Approximately what percentage of people are Rh positive?
Explanation: Blood can be classified on the basis of several factors. Apart from the ABO blood grouping system, the Rh blood grouping is widely used. Around 80% of people are Rh positive (Rh+ve).
6. Which of these structures prevent the mixing of fetal blood with mother’s blood?
a) Amniotic fluid
Explanation: The placenta prevents the mixing of the blood of the fetus with the blood of the mother. The placenta provides oxygen and nutrients to the fetus and removes carbon dioxide and waste products.
7. What antibodies are formed when a Rh-negative mother bears a Rh-positive child?
a) Rh antibodies are formed in the mother
b) Rh antibodies are formed in the fetus
c) Rh antibodies are formed during the second pregnancy
d) Rh antibodies are formed in both
Explanation: When a Rh-negative mother bears a Rh-positive child, the placenta prevents the mixing of their blood. If their bloods come in contact with each other, Rh antibodies are formed in the mother.
8. Which of these does not happen to the baby during erythroblastosis fetalis?
c) Swollen liver
d) High erythrocyte count
Explanation: When a Rh-negative mother produces antibodies to an antigen in the blood of a Rh-positive fetus, it leads to a condition known as erythroblastosis fetalis, which is characterized by jaundice, anemia and a swollen liver in the baby.
9. How can erythroblastosis fetalis be avoided?
a) By administering Rh antibodies to the mother
b) By administering anti-Rh antibodies to the baby
c) By administering anti-Rh antibodies to the mother
d) By administering anti-Rh antibodies to both
Explanation: When a Rh-negative mother produces antibodies to an antigen in the blood of a Rh-positive fetus, it leads to a condition known as erythroblastosis fetalis. It can be avoided by administering anti-Rh antibodies to the mother.
10. Fibrins trap destroyed formed elements during blood clotting. True or false?
Explanation: During the process of blood clotting or coagulation, a network or mesh of fibrin is formed over the wound. This traps the destroyed formed elements, which are the RBCs, WBCs and the platelets.
11. Which of these are not involved in the coagulation of blood?
Explanation: The activities of various enzymes make blood coagulation possible. Thrombokinase, an enzyme complex, fibrin, a mesh covering the wound, and thrombin are involved in blood coagulation.
12. Where is prothrombin present?
a) Inside lymphocytes
b) Inside thrombocytes
c) In the plasma
d) On the surface of RBCs
Explanation: Prothrombin is present in the plasma of blood. Prothrombin is the inactive form of thrombin. Thrombin is the enzyme that converts the inactive fibrinogen to fibrin, which is a mesh that covers wounds.
13. What is the network of threads in a coagulum known as?
b) Clotting factors
d) Formed elements
Explanation: The network of threads or the mesh in a coagulum or clot is known as fibrin. It covers the wound and traps the destroyed formed elements of blood. Fibrin is the active form of fibrinogen.
14. Which of these activates fibrinogen?
Explanation: The inactive fibrinogen is converted into its active form, fibrin, with the help of the enzyme thrombin. Thrombin is the active form of prothrombin, which is present in the blood plasma.
15. Which of these ions play an important role in blood clotting?
a) Sodium ions
b) Calcium ions
c) Potassium ions
d) Phosphate ions
Explanation: Calcium ions play an important role in blood clotting or coagulation as it is needed for the activation of various clotting factors. It is required for the formation of the fibrin mesh network that covers the wound.
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