On the molecular level, why does lifting weights consume energy? A. To contract a muscle, acetylcholine binds and pulls calcium ions. ATP binding and hydrolysis are required in the cycle of acetylcholine and calcium-binding and unbinding. B. To contract a muscle, myosin and actin filaments shorten, requiring ATP binding and hydrolysis. O C. To contract a muscle, myosin binds and pulls actin, ATP binding and hydrolysis are required in the cycle of myosin and actin-binding and unbinding. D. To contract a muscle, acetylcholine and calcium filaments shorten, requiring ATP binding and hydrolysis.

On the molecular level, why does lifting weights consume energy? A. To contract a muscle, acetylcholine binds and pulls calcium ions. ATP binding and hydrolysis are required in the cycle of acetylcholine and calcium-binding and unbinding. B. To contract a muscle, myosin and actin filaments shorten, requiring ATP binding and hydrolysis. O C. To contract a muscle, myosin binds and pulls actin, ATP binding and hydrolysis are required in the cycle of myosin and actin-binding and unbinding. D. To contract a muscle, acetylcholine and calcium filaments shorten, requiring ATP binding and hydrolysis.

BIOLOGY:CONCEPTS+APPL.(LOOSELEAF)

10th Edition

ISBN:9781305967359

Author:STARR

Publisher:STARR

Chapter32: Structural Support And Movement

Section: Chapter Questions

Problem 12SA

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Muscle contraction is the result of critical steps characterized by conformational changes to protein structures in the supramolecule. Which of the following conformational changes requires energy, i.e. ATP hydrolysis? A. Binding of calcium to tropomyosin changing its conformation and exposing a binding site in troponin B. Binding of myosin to troponin resulting in the power stroke and cross-bridge cycle of muscle contraction. C. Disruption in the binding of the myosin head to troponin preceding its release and relaxation back to its activated form. D. Binding of ATP to the myosin head bound to troponin.
Myosin binds to actin, then bends. What is ATP needed for next? A. to pump the Ca++ “keys” back into the sarcoplasmic reticulum B. to replace the strap and cover the binding sites C. to give feedback to the neuron that contraction occurred D. to un-bind myosin from actin and re-set for another powerstroke.
A. nerve cell releases neurotransmitter which stimulates the muscle cell: B. calcium is released from sarcoplasmic reticulum and floods sarcoplasm; C. sarcolemma is permeable to sodium allowing sodium to rush into cell; D. myosin forms cross-bridges to pull actin into the center of the sarcomere; E. sarcolemma depolarizes and conducts an action potential Put them in order
What do skeletal muscle contractions share in common with smooth muscle contractions?a. Both types of contractions do not require calcium ions for a contraction to occur.b. Both types of contractions generate little force or a weak force.c. Both types of contractions consume very little ATP.d. Both types of contractions result from thick and thin filaments sliding past one another.
The functions of tropomyosin in skeletal muscle include A. releasing calcium ions after initiation of contraction. B. generating ATP which it passes to the contractile mechanism. C. binding to myosin during contraction. D. acting as a relaxing protein at rest by covering up the sites where myosin binds to actin. E. sliding on actin to produce shortening.
Which of the following statements is true of the chameleon tongue but not of the human tongue? A. It is a muscular hydrostat. B. Force generation reflects the binding of myosin crossbridges to actin thin filaments. C. The organization of the actin and myosin filaments produces a regular pattern of bands, or striations. D. Gaps or holes in the Z-discs allow supercontraction (shortening beyond the normal limit). E. All of the above statements are true of both the chameleon tongue and the human tongue.
What is the role of ATP in muscle function? a. ATP provides energy that enables myosin to form cross bridges with actin. b. ATP enables myosin to detach from actin. c. ATP provides energy to transport calcium back into storage. d. all of the above
With regard to muscle contraction, which of the following is an INCORRECT statement with regard to the interactions of filaments that occur in the sarcomere? A. When muscles are relaxed tropomyosin blocks binding sites on actin subunits, which keeps cross-bridges from forming. B. The myosin heads conduct a power stroke motion to slide when bound to actin, to move the "thin" filaments towards the center of the sarcomere. C. During contraction, actin subunits are removed from the ends of the "thin" filaments to shorten actin polymers, thus reducing the length of the sarcomere. D. "Thick" filaments are anchored at the M-line, while "thin" filaments are anchored at the Z-line. E. Numerous myosin heads engage with the actin filaments simultaneously, such that there is no back-slipping during the contraction process.
The primary role of calcium in skeletal muscle contraction? Select one: a. Cause depolarization of the sarcolemma b. Cross-bridge cycle between actin and myosin C. Provides energy necessary for contraction d. Causes muscle relaxation e. Regulate ionic composition of the cell
What role (function) does calcium have within a muscle fiber? a. trigger muscle potentials along t-tubules b. trigger contraction by causing the formation of cross bridges c. trigger exocytosis of ACh across the synaptic space d. trigger action potentials along axons e. open voltage gates within the sarcoplasmic reticulum 2. Which of the following are regulatory proteins that allow a muscle fiber to contract when calcium is present? (select all that apply) dystrophin troponin myosin tropomyosin actin 3. During this phase of an action potential, potassium ions exit the cell through voltage gated potassium channels. a. depolarization b. repolarization c. glycolysis d. cross bridge formation
In muscle cells, myosin molecules continue moving along actin molecules as long as: A. ATP is present and intracellular Ca2+ is high. B. ADP is present and intracellular acetylcholine is high. C. ATP is present and troponin is not bound to Ca2+. D.ATP is present and intracellular Ca2+ is low. E. ADP is present and tropomyosin is released from intracellular stores. QUESTION 27 Lamellipodia and filopodia frequently occur near the edges of cells. These membrane features: A. are supported by intermediate filaments, such as keratin. B. result from the polymerization of actin filaments. C. result from the contraction of actin-myosin. D. probably do not serve any useful purpose to the cell. E. are directly linked to the microtubule organizing center. QUESTION 28 Sort the following events to reflect the sequence during smooth muscle contraction upon delivery of muscle stimu 3. Activation of the myosin light-chain kinase 5. Interaction of myosin head with actin 4. Phosphorylation of myosin 1.…
An ion that is essential for muscle contraction is Ca2+. Which of the following statements about the calcium ion and muscle contractions is TRUE? Select one: a. Muscle contractions can occur whether Ca2+ concentrations are high or low. b. Ca2+ binds to the tropin-tropomyosin protein complex shifting it out of the way and allows the myosin to bind to the actin so contraction can occur. c. When Ca2+ concentrations are high, tropomyosin inhibits myosin binding and the muscle is relaxed. d. Ca2+ ions are stored in the sacroplasmic reticulum during the muscle contractions. i do not knwo which one is the answer