1. What is an antigen?
A. A type of cell
B. A molecule that induces an immune response
C. A protein produced by B cells
D. A lipid in cell membranes
Answer: B. A molecule that induces an immune response
2. Antibodies are also known as:
A. Immunoglobulins
B. Antigens
C. Cytokines
D. Enzymes
Answer: A. Immunoglobulins
3. Which cells produce antibodies?
A. T cells
B. B cells
C. Macrophages
D. Neutrophils
Answer: B. B cells
4. The variable region of an antibody is responsible for:
A. Binding to antigens
B. Activating complement
C. Neutralizing pathogens
D. Cell signaling
Answer: A. Binding to antigens
5. Antigens are recognized by antibodies at specific sites called:
A. Paratopes
B. Epitopes
C. Allergen sites
D. Effector sites
Answer: B. Epitopes
6. The main function of antibodies is to:
A. Destroy pathogens directly
B. Neutralize or mark pathogens for destruction
C. Produce cytokines
D. Activate B cells
Answer: B. Neutralize or mark pathogens for destruction
7. The heavy chain of an antibody determines its:
A. Specificity
B. Affinity
C. Class or isotype
D. Variable region
Answer: C. Class or isotype
8. IgG antibodies are most abundant in:
A. The respiratory tract
B. Blood and extracellular fluid
C. Mucosal surfaces
D. The gastrointestinal tract
Answer: B. Blood and extracellular fluid
9. Which antibody is primarily involved in allergic reactions?
A. IgG
B. IgA
C. IgM
D. IgE
Answer: D. IgE
10. Antibodies that form pentamers are classified as:
A. IgA
B. IgG
C. IgM
D. IgE
Answer: C. IgM
11. The antigen-binding fragment of an antibody is known as:
A. Fc region
B. Fab region
C. Hinge region
D. Constant region
Answer: B. Fab region
12. Opsonization is a process where antibodies:
A. Neutralize toxins
B. Mark pathogens for phagocytosis
C. Activate T cells
D. Lyse infected cells
Answer: B. Mark pathogens for phagocytosis
13. Antibodies are primarily produced in response to:
A. Cytokines
B. Antigen exposure
C. Cell apoptosis
D. Complement activation
Answer: B. Antigen exposure
14. Which immunoglobulin is found in breast milk?
A. IgM
B. IgA
C. IgG
D. IgE
Answer: B. IgA
15. Antigen-presenting cells include:
A. Neutrophils and basophils
B. Macrophages, dendritic cells, and B cells
C. T cells and plasma cells
D. Erythrocytes and platelets
Answer: B. Macrophages, dendritic cells, and B cells
16. The Fc region of an antibody is involved in:
A. Antigen binding
B. Effector functions such as complement activation
C. Neutralizing pathogens
D. Epitope recognition
Answer: B. Effector functions such as complement activation
17. The first antibody produced in response to infection is:
A. IgA
B. IgG
C. IgE
D. IgM
Answer: D. IgM
18. Memory B cells are responsible for:
A. Immediate immune response
B. Long-term immunity
C. Antigen presentation
D. T cell activation
Answer: B. Long-term immunity
19. Monoclonal antibodies are produced from:
A. A single clone of B cells
B. Multiple B cell clones
C. T cells
D. Plasma cells
Answer: A. A single clone of B cells
20. Cross-reactivity of antibodies occurs when:
A. Antibodies bind to unrelated antigens with similar epitopes
B. Antibodies activate T cells
C. Antibodies neutralize toxins
D. Antibodies cause cell lysis
Answer: A. Antibodies bind to unrelated antigens with similar epitopes
21. What type of bond stabilizes the antigen-antibody interaction?
A. Covalent bonds
B. Hydrogen bonds and van der Waals forces
C. Ionic bonds
D. Disulfide bonds
Answer: B. Hydrogen bonds and van der Waals forces
22. Antibodies contribute to immunity by activating:
A. Red blood cells
B. Complement proteins
C. Hormones
D. Enzymes
Answer: B. Complement proteins
23. What are polyclonal antibodies?
A. Antibodies produced by a single B cell clone
B. A mixture of antibodies targeting different epitopes
C. Antibodies used in vaccination
D. Synthetic antibodies
Answer: B. A mixture of antibodies targeting different epitopes
24. Antigens can be classified as:
A. Proteins and lipids only
B. Proteins, carbohydrates, lipids, and nucleic acids
C. DNA molecules only
D. Cell organelles only
Answer: B. Proteins, carbohydrates, lipids, and nucleic acids
25. Neutralizing antibodies are effective because they:
A. Destroy pathogens directly
B. Prevent pathogens from infecting cells
C. Activate T cells
D. Lyse cells through apoptosis
Answer: B. Prevent pathogens from infecting cells
26. Hapten is a molecule that:
A. Is a complete antigen
B. Requires a carrier to become immunogenic
C. Stimulates T cells
D. Neutralizes toxins
Answer: B. Requires a carrier to become immunogenic
27. Antibodies with high affinity bind antigens:
A. Weakly and temporarily
B. Tightly and specifically
C. Only after complement activation
D. Only during the primary response
Answer: B. Tightly and specifically
28. Autoantibodies are produced when:
A. Antibodies target foreign antigens
B. Antibodies mistakenly target self-antigens
C. Antibodies neutralize toxins
D. Antibodies activate T cells
Answer: B. Antibodies mistakenly target self-antigens
29. Passive immunity involves:
A. Activation of T cells
B. Transfer of ready-made antibodies
C. Production of memory cells
D. Inflammation at the infection site
Answer: B. Transfer of ready-made antibodies
30. Vaccination works by stimulating the production of:
A. Antigens
B. Antibodies and memory cells
C. Toxins
D. Complement proteins
Answer: B. Antibodies and memory cells
