This set of Immunology Multiple Choice Questions & Answers (MCQs) focuses on “Complement System”.
1. Which of the following pathways come under adaptive immunity?
a) Classical pathway
b) MB-Lectin pathway
c) Alternative pathway
d) Both Alternative and MB-Lectin pathways
View Answer
Explanation: The classical pathway is the adaptive complement pathway. It is one of the three pathways which activate the complement system.
2. Which of the following pathways come under innate immunity?
a) Classical pathway
b) MB-Lectin pathway
c) Alternative pathway
d) Both Alternative and MB-Lectin pathways
View Answer
Explanation: The alternative and MB-lectin pathway are the innate complement pathways. Both of these are of the three pathways which activate the complement system.
3. In classical pathway, the head of the C1q interacts with the _______ domain of Fc of the antibody.
a) CH1
b) CH2
c) CH3
d) Hinge Region
View Answer
Explanation: C1q is a protein complex involved in complement activation. In classical pathway, the head of the C1q interacts with the CH2 domain of Fc of the antibody.
4. C1r and C1s have enzymatic activities because _________
a) Of the conformational changes
b) Of the binding capacity
c) It can form complex
d) It is a complement protein
View Answer
Explanation: Because of the conformational change, both C1r and C1s complement proteins have the enzymatic activity. Not all complement proteins can act as enzymes.
5. C4b2a BAR is called as _________
a) C3 convertase
b) C4 convertase
c) C2 convertase
d) C5 convertase
View Answer
Explanation: C4b2a BAR is called as C3 convertase because it converts inactive C3 protein into active form by cleaving it into C3a and C3b.
6. C3 hydrolysis plays an important role in all the three pathways. True/False?
a) True
b) False
View Answer
Explanation: Yes, all the three pathways require C3 hydrolysis. C3 component is very much important in activating the complement and also in activating phagocytosis by acting as opsonin.
7. The protein which catalyzes the proteolytic cleavage of the complement proteins is called_________
a) A convertase
b) A protease
c) A complement enzyme
d) A complement cleavase
View Answer
Explanation: A convertase is a protein which catalyzes the proteolytic cleavage of the complement proteins. There are convertases like C3 convertase and C5 convertase.
8. What are all the smaller fragments that are formed in the classical pathway responsible for?
a) MAC formation
b) Inflammatory reactions
c) To act as convertases
d) To polymerase C9
View Answer
Explanation: All the smaller fragments that are formed during the proteolytic cleavage of complement proteins are responsible for the inflammatory reactions. They act as mediators in the release of cytokines.
9. In alternative pathway, why is the C3b deposition more?
a) Because of spontaneous hydrolysis of C3
b) Because of catalysis of C3
c) Because of conformational change of C3
d) Because of convertase property of C3
View Answer
Explanation: In alternative pathway, C3 undergoes spontaneous hydrolysis and continuously produces C3a and C3b. Because of this C3b deposition is more on the surface of the cell.
10. In alternative pathway, C3b forms the complex with__________
a) Factor D
b) Factor B
c) C3a
d) Properdine
View Answer
Explanation: C3b forms a complex with Factor B in the alternative pathway. This complex is cleaved by Factor D to give Ba and Bb fragments.
Sanfoundry Global Education & Learning Series – Immunology.
To practice all areas of Immunology, here is complete set of 1000+ Multiple Choice Questions and Answers.
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