PMDC Verified
Question 46 of 99
In the Y-shaped structural architecture of an antibody molecule, the variable antigen-binding domains are located at the:
A
Upper tips of the Fab arms
B
Lower base of the Fc stem
C
Middle hinge region
D
Transmembrane anchor tail
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.
Propolis Cognitive Error Autopsy
Official Correct Choice:
Option A: Upper tips of the Fab arms
Concept: Anatomy of the Y-shaped immunoglobulin molecule.
Solution: The variable domains of both heavy and light chains form the upper tips of the Fab (fragment antigen-binding) arms on the Y-shaped antibody structure.
Why other options are incorrect:
Solution: The variable domains of both heavy and light chains form the upper tips of the Fab (fragment antigen-binding) arms on the Y-shaped antibody structure.
Why other options are incorrect:
- Option B: The lower base of the stem consists of constant heavy chain domains (Fc fragment).
- Option C: The middle hinge allows flexibility between Fab arms and Fc stem.
- Option D: The transmembrane tail anchors membrane-bound BCRs, not the variable binding sites.
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.
Want to solve full-length papers under timed exam conditions?
Practice with zero-scroll lockdown sprints, dynamic latency zone timers, live peer selection telemetry, and the automated Amber mistake recovery loop.