Easily one of the most missed because people THOUGHT they knew:
PIC: HISTO of muscle fiber. Can you do these if arrows are everywhere?
1) Point to myosin fibers
2) Point exactly where ATP works/acts in EM.
3) To what does Ca bind to (answer is diff for smooth and skeletal muscle)
ANSWER ME, PLEEEAASE! (Well, silently, I cannot actually hear you)