Myosin heads have binding sites for see concept 50.5 (page 1124) myosin heads have binding sites for see concept 50.5 (page 1124) actin and calcium atp and actin tropomyosin and actin atp and calcium tropomyosin and troponin

The answer is; ATP binding site and Actin binding site.  When ATP is bound to its site in the head of the myosin the myosin is not attached to actin. Upon hydrolysis of the ATP, the myosin head changes conformation and attaches to its myosin site on the actin to form a cross-bridge between the two filaments.

ecological efficiency: % of usable energy transferred as

biomass from one trophic level to the next typical is 10% efficient (90% of

energy is lost),is diagramed as the pyramid of energy flow. then osprey eagle

are tertiary consumer and the shrimp are primary consumer, so to balance

mass of shrimp (1/0.1) / 0.1 = 100 kg 

a symbiotic relationship with the mitochondria