Answer and 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, tropomyosin is obstructing binding sites for myosin on the thin filament. 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 released. Myofilaments slide impulsed by chemical energy collected in myosin heads, producing a power stroke. 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.
What are the pairs i need them before i can try to answer
Answer: The answer is C.
C. They're examples of cell organelles.
Explanation: I just looked up the question and I got that answer.
Answer:
It is called mimicry when a living thing copies the appearance of another living thing as a means of protection.
Explanation:
Mimicry is used primarily by living things as a means for protection and to decrease the chances of the living thing being killed. For example, a frog that is prey to a toad could have bright colors (bright color frogs are often poisonous) that don't mean anything to the frog and it's species, but to the toad, the frog is poisonous and should not be eaten, so the toad does not eat the frog because it is brightly colored.
Without mimicry, the frog would have been eaten because it wouldn't have had looked like a poisonous frog, or something that the toad would avoid.
