COMPETITIVE EXAM MCQs SERIES of LIFE SCIENCES for CSIR-UGC NET/JRF, SLET, GATE, and other entrance tests: CELL COMMUNICATION AND CELL SIGNALLING – Innate and adaptive immune system.
Syllabus Outline
- Cells and molecules involved in innate and adaptive immunity.
- Antigens, antigenicity and immunogenicity.
- B and T cell epitopes.
- Structure and function of antibody molecules
- Generation of antibody diversity, monoclonal antibodies and antibody engineering.
- Antigen-antibody interactions, MHC molecules and antigen processing.
- Activation and differentiation of B and T cells and their receptors.
- Humoral and cell-mediated immune responses.
- Primary and secondary immune modulation, the complement system, Toll-like receptors, and cell-mediated effector functions.
- Inflammation, hypersensitivity and autoimmunity.
- Immune response during bacterial, parasitic and viral infections.
- Congenital and acquired immunodeficiencies and vaccines.
This quiz contains concept-based, most frequently asked 25 MCQs of “CELL COMMUNICATION AND CELL SIGNALLING – Innate and adaptive immune system”. Each question has a single correct/most appropriate answer.
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1. During the generation of antibody diversity, the process of somatic hypermutation occurs in B cells. Which of the following statements regarding this process is correct?
A) It occurs in the bone marrow during the pro-B to pre-B cell transition.
B) It is a template-dependent DNA repair mechanism that occurs before antigen exposure.
C) It affects the constant regions of the heavy chain to change the antibody isotype.
D) It involves Activation-Induced Cytidine Deaminase and occurs in the germinal centres.
2. Which of the following is a primary characteristic of the innate immune system?
A) Highly specific recognition of epitopes
B) Immediate response to pathogens
C) Formation of long-term memory cells
D) Requirement for gene rearrangement
3. Why is Aminopterin added to the HAT medium during monoclonal antibody production?
A) To facilitate the fusion of B cells and myeloma cells.
B) To block the de novo pathway of nucleotide synthesis.
C) To provide a substrate for the salvage pathway.
D) To selectively kill hybridoma cells that have lost Hypoxanthine-Guanine Phosphoribosyltransferase.
4. Which receptor type is primarily used by innate immune cells to detect conserved microbial structures?
A) T-cell Receptors
B) B-cell Receptors
C) Pattern Recognition Receptors
D) Major Histocompatibility Complex
5. What is the specific term for the microbial molecules recognised by the innate immune system, such as lipopolysaccharide or double-stranded RNA?
A) Epitopes
B) Pathogen-Associated Molecular Patterns
C) Haptens
D) Cytokines
6. In Type I Hypersensitivity, the “late-phase reaction” is primarily mediated by:
A) Preformed histamine released from mast cell granules.
B) Prostaglandins and leukotrienes are synthesised de novo.
C) Infiltration of eosinophils and Th2 cells.
D) Complement-mediated lysis of target cells.
7. Which cell type bridges the gap between innate and adaptive immunity by acting as a professional Antigen-Presenting Cell?
A) Neutrophils
B) Red Blood Cells
C) Natural Killer Cells
D) Dendritic Cells
8. Natural Killer cells identify targets to kill based on which primary signal?
A) Presence of MHC Class II
B) Absence of MHC Class I
C) Binding to CD4 receptors
D) Recognition of viral DNA in the cytoplasm
9. What is the primary function of Plasma Cells?
A) Phagocytosing bacteria
B) Secreting large amounts of soluble antibodies
C) Killing virally infected cells directly
D) Activating the complement system
10. During B-cell development, “Allelic Exclusion” ensures that:
A) Either one of the parental alleles for an immunoglobulin gene is expressed in a single B cell.
B) Both parental alleles for an immunoglobulin gene are expressed in a single B cell.
C) Only maternal alleles for an immunoglobulin gene are expressed in a single B cell.
D) Only paternal alleles for an immunoglobulin gene are expressed in a single B cell.
11. Which cytokine is often called the ‘Endogenous Pyrogen’ because it induces fever during the innate response?
A) Interleukin-1
B) Interleukin-10
C) Transforming Growth Factor-β
D) Erythropoietin
12. How does the adaptive immune system achieve such high diversity in its receptors?
A) By having thousands of different genes for every possible pathogen.
B) Through recombination of specific gene segments.
C) By changing the receptor shape after meeting the pathogen.
D) Using Pattern Recognition Receptors that adapt to new pathogens.
13. Which cell is known for having large granules containing histamine and is central to allergic reactions?
A) Mast Cell
B) Memory B-cell
C) Helper T-cell
D) Monocyte
14. What is the role of the Transporter associated with the antigen processing complex in the immune system?
A) Transporting MHC II molecules from the ER to the Golgi.
B) Transporting peptides from the cytosol into the lumen of the ER.
C) Transporting exogenous antigens from the phagosome to the cytosol.
D) Moving the T-cell receptor to the cell surface.
15. Clonal selection theory explains that:
A) Innate cells divide faster than adaptive cells
B) Lymphocytes with receptors specific to the antigen will proliferate
C) The body makes clones of pathogens to make a large amount of antigen against the pathogens
D) Stem cells produce identical red and white blood cells
16. The process by which antibodies coat a pathogen to make it easier for phagocytes to ingest is called:
A) Opsonisation
B) Apoptosis
C) Neutralisation
D) Chemotaxis
17. Which signalling molecule is primarily responsible for antiviral states in neighbouring cells?
A) Histamine
B) Type I Interferon
C) Insulin
D) Interleukin-4
18. Which of the following is a primary characteristic of “Immunogenicity” that distinguishes it from “Antigenicity”?
A) The ability to bind specifically with the products of an immune response.
B) The presence of multiple epitopes on the surface.
C) The size of the molecule is greater than 10,000 Daltons.
D) The ability to induce a humoral or cell-mediated immune response.
19. Which organ is the primary site for T-cell maturation?
A) Bone Marrow
B) Thymus
C) Spleen
D) Thyroid
20. MHC Class II molecules are found on which of the following cells?
A) All nucleated cells
B) Antigen Presenting Cells
C) Red Blood Cells
D) Neuronal cells
21. Which antibody class is the first to be secreted during a primary immune response?
A) IgG
B) IgE
C) IgA
D) IgM
22. What happens to a T-cell that receives Signal 1 (Antigen) but NO Signal 2 (Co-stimulation)?
A) It divides rapidly
B) It becomes anergic
C) It turns into a Plasma cell
D) It starts secreting antibodies
23. Which of the following statements about MHC Class II molecules is correct?
I – They are expressed primarily on Professional Antigen Presenting Cells.
II – The peptide-binding groove is open at both ends, allowing for longer peptides.
III – They consist of two non-covalently associated glycoprotein chains, α and β.
IV – They present antigens that are synthesised within the cytosol of the cell.
A) I only
B) I and II
C) I, II and III
D) I, II, III and IV
24. Which of the following statements are correct regarding Antibody Engineering?
I – Chimeric antibodies contain human constant regions and murine variable regions.
II – Humanised antibodies contain only murine CDRs grafted onto human frameworks.
III – Diabodies are bivalently linked molecules consisting of two scFv fragments.
IV – Hybrid-hybridomas are used to produce bispecific antibodies.
A) I only
B) I and II
C) I, II and III
D) I, II, III and IV
25. Assertion (A): Secondary immune response is characterised by a shorter lag phase and higher-affinity antibodies compared to the primary response.
Reason (R): Memory B cells have undergone affinity maturation and class switching during the primary response.
A) Both (A) and (R) are true, and (R) is the correct explanation of (A).
B) Both (A) and (R) are true, but (R) is not the correct explanation of (A).
C) (A) is true, but (R) is false.
D) (A) is false, but (R) is true.
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References
- Nelson, David L. & Cox, Michael M. (2021). Lehninger Principles of Biochemistry, W. H. Freeman, 8th Edition.
- Willey, J. M., Sandman, K. M., & Wood, D. H. (2022). Prescott’s Microbiology, McGraw-Hill, 12th Edition
- Kuby, J., Kindt, T. J., Osborne, B. A., & Goldsby, R. A. (2019). Kuby Immunology, W. H. Freeman, 8th Edition.
- Alberts, B., Johnson, A., Lewis, J., Morgan, D., Raff, M., Roberts, K., & Walter, P. (2014). Molecular Biology of the Cell, Garland Science, 4th Edition.
- Geoffrey Cooper and Kenneth Adams (2022). The Cell: A Molecular Approach, Oxford University Press, 9th Edition
- Robert A Weinberg, Robert A. Weinberg (2006). The Biology of Cancer, Taylor & Francis, 1st Edition.
- Gupta, P.K. (2022). Cell and Molecular Biology, Rastogi Publications, 5th Edition.
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