Biol 105 - Example quiz - Muscle

Choose the correct answer for each question.

1 Adenosine triphosphate (ATP) is required in muscle contraction for: Dissociation of myosin and actin only Energizing the myosin head group only Dissociation of myosin and actin and energizing the myosin head group Causing troponin to fall away from tropomyosin None of the above 2 A reduced amount of acetylcholine (ACh) receptor expression at the neuromuscular junction could lead to: Increased Ca ion release from the sarcoplasmic reticulum Failure of the action potential to move down the motor nerve even when the muscle action potential is present. Too much summation of muscle contractions No action potential in the muscle membrane in response to an action potential in the motor nerve. All of the above. 3 Which of the following statements about regulation of muscle contraction is not true? Calcium binds to troponin Tropomyosin covers the myosin binding sites on the actin molecule ATP binds to tropomyosin Myosin and actin can bind when calcium is bound to troponin. All of the above are not true. 4 In an exercise like cycling a repeated series of muscular contractions and relaxations are required. A reduced pedaling frequency could be caused by: Not enough actin fibers Not enough calcium pumps for Ca uptake into the sarcoplasmic reticulum Not enough myosin fibers An increase in muscle sarcoplasmic reticulum. None of the above.