Which of the following regions of a sarcomere at rest is characterized by the presence of myosin only? a) A band b) H zone c) I band d) Z line

Which of the following labeled zones in the electron micrograph of the sarcomere shortens during contraction? OA) B) -E C) 00) D E) -C -8

Which part of a skeletal muscle does shorten during muscular contraction? A) Thick filaments B) Thin filaments C) Z disks D) Sarcomeres

Which of the following statements is unique to skeletal muscle? O a) skeletal muscle has striations O b) skeletal muscle is attached to bones O c) skeletal muscle is under voluntary control O d) skeletal muscle is multinucleated O all of the above O b, c, & d but not a

For the myosin head to form cross bridges with actin, it is necessary for to bind to actin. a) Calcium b) Troponin c) Sarcolemma d) ATP

1. During muscle contraction, hydrolysis of ATP results in A) a change in the conformation of actin B) a change in the conformation of myosin C) association of myosin head to actin D) dissociation of myosin from actin E) no effect on muscle contraction

14) after a muscle fiber has contracted, the calcium a) is secreted by the Golgi apparatus  b) is chemically bound to the myofilaments  c) renters the sarcoplasmic reticulum  d) is destroyed

33) which of the following is released into the synaptic cleft and is responsible for depolarizing the sarcolemma? a) tropomyosin b) acetylcholine  c) troponin  d) cal

Smooth muscles relax when: a) myosin kinase phosphorylates the myosin head b) myosin phosphatase removes a phosphate group from myosin c) Ca2 + binds to calmodulin d) Ca2 + flows out of the sarcoplasmic reticulum

A sarcomere contracts when a) Thin filaments (actin) slide b) Thick filaments (myosin) slide c) Thin filaments (actin) contract d) Thick filaments (myosin ) contract