Multiple Choice
Which of the following statements is true regarding lipophilic hormones such as steroids?
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10. Cell Signaling
Introduction to Cell Signaling
Multiple Choice
Which of the following proteins binds to actin at its binding sites during muscle contraction?
A
Tubulin
B
Myosin
C
Collagen
D
Keratin
Verified step by step guidance1
Understand the context of muscle contraction: Muscle contraction involves the interaction between actin and myosin filaments within the sarcomere, the functional unit of muscle fibers.
Recall the role of actin and myosin: Actin is a thin filament, while myosin is a thick filament. During contraction, myosin heads bind to specific binding sites on actin filaments to form cross-bridges.
Eliminate incorrect options: Tubulin is a protein involved in microtubule formation, not muscle contraction. Collagen is a structural protein found in connective tissues, and keratin is a protein found in hair, nails, and skin. None of these interact with actin during muscle contraction.
Focus on the correct protein: Myosin is the protein that binds to actin at its binding sites during muscle contraction. This binding is essential for the sliding filament mechanism that drives contraction.
Summarize the process: Myosin heads attach to actin binding sites, undergo a power stroke fueled by ATP hydrolysis, and pull the actin filaments closer, shortening the sarcomere and causing muscle contraction.
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