Part 5: Immunity & Immunology (25 MCQs)
Part 5: Immunity & Immunology – Innate and Acquired Immunity, Antibodies, Immune Cells, Basics of Immunology (25 MCQs)
Q101. Immunity refers to:
a) The ability to digest food properly
b) The ability to resist and fight against disease-causing microbes
c) A condition of being infected
d) The process of inflammation only
Answer: b
- b) Correct: Immunity = body’s defense against pathogens.
Q102. Innate immunity is:
a) Present from birth, non-specific
b) Developed after infection
c) Acquired through vaccines
d) Produced by antibiotics
Answer: a
- a) Correct: Innate immunity = inborn, non-specific defense.
Q103. Acquired immunity is:
a) Present at birth
b) Pathogen-specific and memory-based
c) Only provided by mother
d) Always short-lived
Answer: b
- b) Correct: Acquired immunity develops after exposure to pathogens and has memory.
Q104. First line of defense in innate immunity includes:
a) Antibodies
b) Skin and mucous membranes
c) Memory B-cells
d) T-lymphocytes
Answer: b
- b) Correct: Physical barriers (skin, mucosa, tears, saliva) = first line of defense.
Q105. Phagocytic cells (like macrophages, neutrophils) are part of:
a) Innate immunity
b) Acquired immunity
c) Both innate and acquired
d) Autoimmunity
Answer: a
- a) Correct: Phagocytes engulf microbes → innate immunity.
Q106. Acquired immunity has two types:
a) Active and Passive
b) Specific and non-specific
c) Primary and secondary
d) Cellular and humoral only
Answer: a
- a) Correct: Acquired immunity = active (natural infection, vaccines) and passive (antibodies received).
Q107. Immunity from vaccination is:
a) Natural passive
b) Natural active
c) Artificial active
d) Artificial passive
Answer: c
- c) Correct: Vaccination = artificial active immunity.
Q108. Immunity from mother’s milk (IgA antibodies) is:
a) Natural active
b) Natural passive
c) Artificial passive
d) Artificial active
Answer: b
- b) Correct: Colostrum (IgA) provides natural passive immunity.
Q109. Antibodies are produced by:
a) T-cells
b) Macrophages
c) B-lymphocytes (plasma cells)
d) Neutrophils
Answer: c
- c) Correct: B-cells → plasma cells → antibodies (immunoglobulins).
Q110. Which immunoglobulin is abundant in blood?
a) IgA
b) IgM
c) IgG
d) IgE
Answer: c
- c) Correct: IgG is the most abundant antibody in circulation.
Q111. Which immunoglobulin is first produced during infection?
a) IgA
b) IgM
c) IgE
d) IgG
Answer: b
- b) Correct: IgM appears first during infection.
Q112. IgE is associated with:
a) Autoimmune disorders
b) Allergic reactions and parasitic infections
c) Passive immunity
d) Vaccination
Answer: b
- b) Correct: IgE → allergies (histamine release), parasitic defense.
Q113. Which immune cells destroy virus-infected cells?
a) B-cells
b) Helper T-cells
c) Cytotoxic T-cells (CTLs)
d) Plasma cells
Answer: c
- c) Correct: Cytotoxic T-cells kill virus-infected and tumor cells.
Q114. Helper T-cells secrete:
a) Antibodies
b) Cytokines to regulate immune response
c) Histamine
d) Complement proteins
Answer: b
- b) Correct: Helper T-cells release cytokines that activate B- and T-cells.
Q115. Which is a lymphoid organ?
a) Liver
b) Thymus
c) Pancreas
d) Kidney
Answer: b
- b) Correct: Thymus (primary lymphoid organ) → T-cell maturation.
Q116. Primary lymphoid organs are:
a) Spleen and tonsils
b) Bone marrow and thymus
c) Liver and lymph nodes
d) Peyer’s patches
Answer: b
- b) Correct: Bone marrow (B-cells), thymus (T-cells) = primary lymphoid organs.
Q117. Secondary lymphoid organs include:
a) Thymus, bone marrow
b) Spleen, lymph nodes, tonsils, Peyer’s patches
c) Brain, spinal cord
d) Liver, pancreas
Answer: b
- b) Correct: Secondary lymphoid organs = sites of immune interaction.
Q118. Which of the following provides first response to infection (primary immune response)?
a) IgG
b) IgM
c) IgA
d) IgE
Answer: b
- b) Correct: IgM is produced first → primary immune response.
Q119. Secondary immune response is stronger due to:
a) Phagocytosis
b) Memory B- and T-cells
c) Histamine release
d) Vaccination only
Answer: b
- b) Correct: Memory cells → rapid, stronger secondary response.
Q120. Which type of immunity provides long-term protection?
a) Innate immunity
b) Active acquired immunity
c) Passive acquired immunity
d) Artificial passive only
Answer: b
- b) Correct: Active acquired immunity (infection/vaccine) → long-lasting.
Q121. Antigens are:
a) Substances that stimulate immune response
b) Antibodies produced by plasma cells
c) Enzymes secreted by microbes
d) Complement proteins
Answer: a
- a) Correct: Antigen = foreign substance triggering antibody production.
Q122. The complement system is part of:
a) Adaptive immunity only
b) Innate immunity (but enhances adaptive)
c) Autoimmunity
d) Allergic response
Answer: b
- b) Correct: Complement proteins = innate defense, aid adaptive response.
Q123. Interferons are secreted by:
a) Virus-infected cells
b) B-cells
c) Plasma cells
d) Macrophages only
Answer: a
- a) Correct: Virus-infected cells secrete interferons → protect neighboring cells.
Q124. Which immune cells present antigens to T-cells?
a) Neutrophils
b) Macrophages, dendritic cells
c) Plasma cells
d) RBCs
Answer: b
- b) Correct: Antigen-presenting cells (APCs) → macrophages, dendritic cells.
Q125. Which type of immunity is quicker but short-lived?
a) Innate immunity
b) Active immunity
c) Passive immunity
d) Vaccination
Answer: c
- c) Correct: Passive immunity (antibody transfer) → immediate but temporary protection.
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