Biology Immunity PMDC Conceptual Practice
PMDC Verified Question 53 of 99
Which of the following biological components is NOT part of the innate first line of defense?
A
Interferon
B
Intact epidermis
C
Sebum
D
Perspiration
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option A: Interferon
Concept: First vs. second line innate defenses.

Solution: The first line of defense consists of external physical and chemical barriers (skin, sebum, perspiration). Interferon is an internal signaling protein activated after pathogens bypass barriers, placing it in the second line of defense.

Why other options are incorrect:
  • Option B: The intact epidermis is a primary physical barrier preventing pathogen entry.

  • Option C & Option D: Sebum and perspiration are chemical secretions present on skin surfaces containing antimicrobial fatty acids and lysozyme.

Quality & Fidelity Assurance: Every question on BeambePrep is rigorously curated against the official PMDC syllabus with zero filler, zero out-of-syllabus content, and zero typos. When an authentic past paper originally contained a historical mistake or ambiguity from the examining board (such as UHS or NUMS), BeambePrep faithfully reflects the original paper while detailing the nuance and scientific consensus in the autopsy above.

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