Match each term with its corresponding description regarding the sliding filament theory.
-protein that directly prevents the formation of cross-bridges in the sarcomere
A)Troponin
B)Myosin
C)Actin
D)T-tubules
E)ATP
F)Calcium
G)Cross-bridges
H)Tropomyosin
I)Acetylcholine

Question

Quizplus · Accepted Answer

Tropomyosin is a protein that directly prevents the formation of cross-bridges in the sarcomere by blocking the binding site on actin for myosin.

Answer: A
 Troponin is a protein complex that regulates the position of tropomyosin on the thin filament, which in turn controls the availability of the binding site on actin for myosin.

Answer: C
 Actin is a thin filament composed of globular protein subunits that contain binding sites for myosin and participate in the sliding of filaments during muscle contraction.

Answer: D
 T-tubules are invaginations of the sarcolemma, or muscle cell membrane, that allow for the rapid transmission of action potentials, or electrical signals, deep into muscle fibers.

Answer: E
 ATP, or adenosine triphosphate, is the primary source of energy for muscle contraction and is required for the release and reuptake of calcium ions from the sarcoplasmic reticulum.

Answer: F
 Calcium ions are released from the sarcoplasmic reticulum in response to an action potential and bind to troponin, causing a conformational change that moves tropomyosin and exposes the binding site on actin for myosin.

Answer: G
 Cross-bridges are formed when myosin heads bind to the exposed binding sites on actin, causing the filaments to slide past each other and resulting in muscle contraction.

Answer: I
 Acetylcholine is a neurotransmitter that is released from motor neurons and binds to receptors on the muscle cell membrane, triggering an action potential and ultimately leading to muscle contraction.

Match Each Term with Its Corresponding Description Regarding the Sliding