USING FIGURE A, label:
a Axon Terminal
b. Synaptic Vesicle
c. Synaptic Clutt d. ACh
o. ACh receptors 1. Motar End Plate
2 REFER to FIGURE B, what chemical signal allows the black spheres to exit the superiorly located structure?
Calcium ion (Ca2+)
3. How does this system "reset" for the next action potential that is arriving? In the figure above, clearly label.
a Troponin
b. Tropomyosin
c. Myosin
2. What is the role of Call in this
Calcium ion (Ca2+) triggers muscle contraction by binding to troponin which causes a conformational change in tropomyosin, exposing myosin binding sites on actin filaments.
3. Explain why this process is called the sliding filament hypothesis.
Because actin and myosin filaments slide past each other during contraction, then slide back into place during relaxation.
4. Does this image indicate the BEGINNING or END of a contraction? Explain your choice.
This image indicates the beginning of a contraction. Myosin heads have just bound to actin filaments but the filaments have not started sliding yet.
5. Where, in the muscle cell, is this picture taken from?
This shows the actin and myosin filaments in the sarcomere, the contractile unit of muscle cells.