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QLDBiologyQuick questions
Unit 2: Maintaining the internal environment
Quick questions on Innate and adaptive immune responses (QCE Biology Unit 2)
7short Q&A pairs drawn directly from our worked dot-point answer. For full context and worked exam questions, read the parent dot-point page.
What is first line of defence?Show answer
Physical and chemical barriers stop pathogens entering the body in the first place. Non-specific.
What is antigen presentation?Show answer
Phagocytes and dendritic cells display fragments of digested pathogens on MHC class II molecules and travel to a lymph node. There they present the antigen to T cells.
What is primary response?Show answer
First exposure to an antigen. Slow (5 to 10 days to peak), produces lower antibody levels, generates memory cells. The host typically experiences symptoms.
What is secondary response?Show answer
Second (or later) exposure to the same antigen. Memory cells respond rapidly (within hours to a few days), produce higher antibody levels (mostly IgG) and often clear the pathogen before symptoms appear. This is the basis of long-term immunity and vaccination.
What is q1?Show answer
Distinguish between humoral and cell-mediated adaptive immunity, naming the principal cell type and the targets of each. [3 marks]
What is q2?Show answer
A blood test on a patient three weeks after infection with SARS-CoV-2 shows IgM declining, IgG rising and memory B cell count elevated. Identify the phase of immune response and justify the IgG dominance. [3 marks]
What is q3?Show answer
Refer to the inflammatory response. (a) Identify three cardinal signs and name the chemical mediators responsible. (b) Explain how phagocytosis bridges innate and adaptive immunity.
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