The sarcomere shortens when the myosin heads of the thick filaments, in a cocked position, form cross bridges with the actin molecules in thin filaments. this activity will test your understanding of the steps that occur in one complete cross bridge cycle. place the steps that occur during a single cross bridge cycle in the correct order from left to right.

Here are the steps;

step 1. The activated myosin head binds to actin, forming a cross bridge.

Step 2. ADP is released and myosin slides the thin filament toward the center of the sarcomere.

step 3. ATP binds to the myosin head and detaches it from actin

step 4. ATP is hydrolyzed to ADP and P(i) and the energy released re-elevates the myosin head.

unicellular organisms, like bacteria, are able to perform all life functions within one single cell. multicellular organisms need many different types of cells to carry out the same life processes. each of these special types of cells has a different structure that it perform a specific function.