Biology Support & Movement ETEA 2023 Retake
PMDC Verified Question 37 of 75
How many actin filaments surround the myosin at each end?
A
2
B
4
C
6
D
8
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option C: 6
Concept:

Cross-sectional lattice geometry of the sarcomere.

Formula:

N/A (Conceptual)

Solution:

  • To maximize contraction force, thick and thin filaments are tightly packed into a crystalline lattice.


  • In vertebrate skeletal muscle, taking a slice through the zone of overlap reveals a hexagonal arrangement.


  • Exactly 6 thin actin filaments geometrically surround every single thick myosin filament.


Why other options are incorrect:

The geometry strictly dictates a hexagon (6). Any other number would result in inefficient structural gaps or impossible protein binding angles.

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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