Muscle contraction is triggered by an increase in the concentration of calcium ions that bind to:
A) vimentin
B) myosin
C) tropomyosin
D) troponin
E) actin
IMAT 2025 · Question 16
Q16 - Muscle contraction
Pinned
The correct answer is D) troponin.
At rest, tropomyosin covers the binding sites on actin. When calcium is released, it binds to troponin, and troponin pulls tropomyosin out of the way so myosin can attach.
Don't pick tropomyosin (C): it moves, but troponin is the protein that actually binds the calcium.
Replies 0
No other replies yet.
Log in to reply.