Match each term with its corresponding description regarding the sliding-filament theory.
-Protein that directly prevents the formation of cross-bridges in the sarcomere

Question

Quizplus · Accepted Answer

Tropomyosin binds to actin and blocks the binding site for myosin on actin, preventing the formation of cross-bridges in the absence of calcium.

Answer: A
 Troponin is the protein complex that binds calcium ions and moves tropomyosin out of the way, exposing the myosin-binding sites on actin.

Answer: G
 Cross-bridges are the connections formed between myosin heads and actin filaments during muscle contraction.

Answer: F
 Calcium ions bind to troponin, causing a conformational change in the troponin-tropomyosin complex, which allows the myosin-binding sites on actin to be exposed.

Answer: B
 Myosin is the motor protein that binds to actin and moves the actin filaments relative to the myosin filaments, which results in muscle contraction.

Answer: C
 Actin is the thin filament that, along with myosin, makes up the muscle sarcomere.

Answer: E
 ATP provides the energy needed for myosin to bind to actin and move the actin filaments relative to the myosin filaments.

Answer: D
 T-tubules are invaginations of the muscle cell membrane that help to transmit the action potential deep into the muscle fiber, triggering the release of calcium ions from the sarcoplasmic reticulum.

Answer: I
 Acetylcholine is a neurotransmitter that is released by motor neurons at the neuromuscular junction and binds to receptors on the muscle fiber sarcolemma, triggering an action potential that leads to muscle contraction.

Match Each Term with Its Corresponding Description Regarding the Sliding-Filament