When a muscle cell contracts, Group of answer choices the position of each myosin head is identical at any given moment. some my
osin heads bind to actin molecules as other myosin heads release from actin molecules. the myosin heads each produce a single power stroke. the intracellular calcium concentration remains unchanged.
When a muscle cell contracts, the myosin heads each produce a single power stroke.
Explanation:
In rest, attraction strengths between myosin and actin filaments are inhibited by the tropomyosin. When the muscle fiber membrane depolarizes, the action potential caused by this depolarization enters the t-tubules depolarizing the inner portion of the muscle fiber. This activates calcium channels in the T tubules membrane and releases calcium into the sarcolemma. At this point, <em>tropomyosin is obstructing binding sites for myosin on the thin filament</em>. When calcium binds to the troponin C, the troponin T alters the tropomyosin by moving it and then unblocks the binding sites. Myosin heads bind to the uncovered actin-binding sites forming cross-bridges, and while doing it ATP is transformed into ADP and inorganic phosphate which is liberated. Myofilaments slide impulsed by chemical energy collected in myosin heads, <u>producing a power stroke</u>. The power stroke initiates when the myosin cross-bridge binds to actin. As they slide, ADP molecules are released. A new ATP links to myosin heads and breaks the bindings to the actin filament. Then ATP splits into ADP and phosphate, and the energy produced is accumulated in the myosin heads, which starts a new binding cycle to actin. Z-bands are then pulled toward each other, thus shortening the sarcomere and the I-band, and producing muscle fiber contraction.
Rodenticide because it has the word "rodent" meaning, a mammal of the order Rodentia, which mice and rats are included in. Therefore, the answer is rodenticide.
Purple is the dominant color in hedgehogs and yellow is recessive. Cross 2 heterozygous individuals with each other. What percentage of the offspring will carry the purple allele? one over four
An animal cell lacking carbohydrates on the external surface of its plasma membrane would likely be impaired in CELL TO CELL RECOGNITION. Carbohydrates have diverse functions, one of their functions is that they serve as a recognition signal at the surface of cells. Carbohydrates located on the surface of cells enable cells to recognize and communicate with one another.
