9 Questions
What happens when Ca$^{2+}$ binds to troponin C (TnC) in the presence of tropomyosin?
Ca$^{2+}$ binding to TnC shifts the tropomyosin-troponin complex, relieving inhibition and allowing muscle contraction to proceed.
What is the role of tropomyosin in muscle contraction?
Tropomyosin binds lengthwise along actin filaments and, in striated muscle, is associated with a complex of three troponins, regulating the binding of myosin to actin.
What is the result of the actin filaments sliding past the myosin filaments in muscle contraction?
Shortening of the sarcomere without any change in filament length
What happens in the absence of Ca$^{2+}$ in relation to the tropomyosin-troponin complex?
The tropomyosintroponin complex blocks the binding of myosin to actin.
What is the role of tropomyosin in muscle contraction?
Tropomyosin binds lengthwise along actin filaments and, in striated muscle, is associated with a complex of three troponins: troponin I (TnI), troponin C (TnC), and troponin T (TnT).
What happens in the absence of Ca$^{2+}$ in relation to the tropomyosin-troponin complex?
The tropomyosintroponin complex blocks the binding of myosin to actin.
What is the result of the actin filaments sliding past the myosin filaments in muscle contraction?
Shortening of the sarcomere without any change in filament length.
What happens when Ca$^{2+}$ binds to troponin C (TnC) in the presence of tropomyosin?
The tropomyosintroponin complex shifts, relieving inhibition and allowing contraction to proceed.
Which component works in conjunction with troponin to regulate association of tropomyosin and troponins with actin filaments?
Ca$^{2+}$
Test your knowledge on the structural composition of muscle cells, including muscle fibers, myofibrils, actin, and myosin filaments.
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