1. Which of the following is true about muscle protein?

A. In a contracting muscle cell, troponin binds to calcium, andtropomyosin changes conformation and uncovers the myosin bindingsites on actin

B. In a relaxed muscle cell, tropomyosin binds to calcium, andtroponin covers the myosin binding sites on actin

C. In a contracting muscle cell, tropomyosin binds to calcium,and troponin changes conformation and uncovers the myosin bindingsites on actin.

D. In a relaxed muscle cell, troponin binds to calcium, andtropomyosin covers the myosin binding sites on actin

2.

Which of the following represents the CORRECT order of events inthe muscle cell when I decide that I want to wiggle my pinkietoe?

A. The influx of positive charge causes the opening ofligand-gated sodium channels causing an action potential thatpropagates down the sarcoplasmic reticulum membrane which causesthe release of calcium from the T-tubules.

B. The influx of positive charge causes the opening ofvoltage-gated sodium channels causing an action potential thatpropagates down the T-tubule leading to the release of calcium fromthe sarcoplasmic reticulum

C. The influx of positive charge causes the opening ofligand-gated sodium channels causing an action potential thatpropagates down the T-tubule leading to the release of calcium fromthe sarcoplasmic reticulum

D. The influx of positive charge causes the opening ofvoltage-gated sodium channels causing an action potential thatpropagates down the sarcoplasmic reticulum membrane which causesthe release of calcium from the T-tubules.