(a(i))[4]
Outline the structural similarities shared by a neuromuscular junction and a cholinergic synapse.
(a(ii))[3]
ATP hydrolysis during muscle contraction releases inorganic phosphate ($P_i$). Calcium ions ($\text{Ca}^{2+}$) can combine with $P_i$ in the sarcoplasmic reticulum to form insoluble calcium phosphate. This may result in fewer power strokes occurring in sarcomeres. Suggest why calcium phosphate formation in the sarcoplasmic reticulum may result in fewer power strokes occurring in sarcomeres.
(b)[2]
Identify the molecules shown as A and B in Fig. 7.1.