94 Wed 102 PM session masteringaandpcommycttemviewoffsetm ne

94% Wed 1:02 PM session masteringaandpcom/myct/temview?offsetm neat&assignmentProblemIDs81954401; soned in as manam Eirajeldin w Focus Figure 9.3: Cross Bridge Cycle rag and drop the terms to the best description of terms the crossbridge formation. Answers may be used once or not at all. involving Reset Help cytoplasm 1. Location of higher concentration of ca needed for cross bridge formation and cyding: energized cocked myosin 2. Actin status to begin cross bridge formation. extracellular fluid actin binding sites exposed J 3 Molecule(s) bound to the myosin head of the cross bridge cycle at the start actin binding sites blocked 4. Energy state of myosin for beginning cross bridge formation: ADP and Pi low-energy myosin head Submit Hints My Answers Give up Review Part MacBook Air

Solution

4. Energized cocked myosin head

3.ATP

This is because at rest, the myosin head is bound to an ATP molecule in a low-energy configuration . At this time it is unable to access the cross-bridge binding sites on the actin.The myosin head can hydrolyze ATP into ADP and an inorganic phosphate ion. A portion of the energy released in this reaction changes the shape of the myosin head and promotes it to a high-energy configuration.

1.

2.Actin binding sites exposed

When intracellular calcium levels are low, the muscle cell is relaxed, and tropomyosin molecules block the active binding sites on actin.Ca2+ levels are taken from cytosol and once a sufficient level of calcium is reached, binding sites of actin are exposed for cross bridge Once binding sites on actin are exposed, the events of the cross bridge cycle occur in rapid succession. The tropomyosin is removed when sufficient calcium is present.