Most of them are proteins but there are some RNA and\or DNA enzymes or maybe glycopeptides.
In a dichotomous key you named then by their traits while in a branching diagram it already has the name and it's traits.
A cross bridge cycle occurs when actin (A) combines with myosin (M) and ATP to produce force, adenosine diphosphate (ADP) and inorganic phosphate (Pi). The cross bridge cycle is a series of molecular events that occur after excitation of the sarcolemma.
