Practise 21 real Federal Board questions on Immunity from 2023 to 2026. See the answer and explanation as soon as you answer.
Immunity is one of the 15 main chapters in our Federal Board FSC Biology question bank (11th and 12th class), and about 4% of its real questions come from it. Tayyari Karo has 21 real questions on this chapter from 2023 to 2026; 5 are multiple choice and marked instantly, and the rest are short and long questions with a model answer. By difficulty: 18 medium, 3 easy.
Work through the questions below, then open the explanation for each one. Redo the ones you missed a few days later.
These are real past-paper questions. Think of your answer first, then open the explanation.
Which one of the following is the Therapeutic use of monoclonal antibodies?
Answer: A. Targeted cancer therapy
Monoclonal antibodies are engineered to specifically bind cancer cell antigens, making them useful for targeted cancer therapy.
Antibodies transferred from mother to baby through placenta provide:
Answer: A. Natural passive immunity
Maternal antibodies crossing the placenta give the fetus/newborn ready-made antibodies without its own immune system acting — natural passive immunity.
HIV primarily attacks which type of human cells?
Answer: C. T-helper cells
HIV specifically targets and destroys CD4-bearing T-helper cells, progressively weakening the immune system.
The best way to prevent tetanus is:
Answer: D. Have vaccination
Vaccination (tetanus toxoid) induces active immunity and is the most reliable way to prevent tetanus.
The component of second line of defense in the following is:
Answer: A. Natural killer cell
Natural killer cells are part of innate (second-line) defense; cytotoxic T, helper T and B lymphocytes belong to the third line (specific/adaptive) defense.
Enlist any six stages of HIV life cycle.
1. Attachment of gp120 to CD4 receptor on host T-helper cell. 2. Fusion of viral envelope with the host cell membrane and entry of viral RNA. 3. Reverse transcription of viral RNA into DNA. 4. Integration of viral DNA into the host chromosome (provirus). 5. Transcription and translation of viral genes using host machinery. 6. Assembly of new viral particles and budding from the host cell membrane, releasing mature virions. (Any six.)
a. Describe the role of B-cells in antibody-mediated immunity. b. Draw the structural model of an antibody molecule.
a. Role of B-cells: B-lymphocytes carry unique membrane-bound antibody receptors that recognise a specific antigen. Upon encountering that matching antigen (often with help from helper T-cells), a B-cell is activated and undergoes clonal expansion, differentiating into: (1) Plasma cells, which secrete large quantities of soluble antibodies specific to that antigen into the blood/lymph, where the antibodies neutralise toxins, mark pathogens for destruction (opsonization), and activate complement; and (2) Memory B-cells, long-lived cells that persist after the infection clears, enabling a faster, stronger antibody response if the same antigen is encountered again in future — the basis of long- …
The full model answer is in the app.
T-cells are involved in specific defence. Name any three types of T-cells with their specific roles.
(1) Helper T-cells (TH) — activate B-cells and cytotoxic T-cells and coordinate the immune response by releasing cytokines.
(2) Cytotoxic T-cells (TC) — directly kill infected or cancerous cells by inducing apoptosis.
(3) Memory T-cells — persist after an infection is cleared, enabling a faster, stronger response on re-exposure to the same antigen.
(Suppressor/regulatory T-cells switch off the immune response once the pathogen is eliminated.)
| Session | Questions |
|---|---|
| 2026 Annual | 8 |
| 2025 1st Annual | 1 |
| 2025 2nd Annual | 4 |
| 2024 Annual | 5 |
| 2023 Annual | 3 |
21 real Federal Board (FBISE) Biology questions on Immunity from 2023 to 2026, for 11th and 12th class. Each one shows the session it came from.
No. We could not find an official FBISE marking scheme for these papers, so the answers and explanations are written by Tayyari Karo for practice. Check anything important with your teacher or textbook.
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