Answer:
<u>Once the myosin-binding sites are exposed, and if sufficient ATP is present, myosin binds to actin to begin cross-bridge cycling. Then the sarcomere shortens and the muscle contracts. In the absence of calcium, this binding does not occur, so the presence of free calcium is an important regulator of muscle contraction.</u>
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<span>TRADE OFF occurs during the design process when one benefit is given up in order to obtain another.</span>
Answer:
Enzymes are biological catalysts. Catalysts lower the activation energy for reactions. The lower the activation energy for a reaction, the faster the rate. Thus enzymes speed up reactions by lowering activation energy.
Explanation:
