You know from experience that skeletal muscle tires quite quickly, especially if there is not enough oxygen. Interestingly, shellfish such as clams can maintain a month-long contraction in the muscle that keeps the shell closed. No oxygen gets in this situation. These muscles have a different version of myosin called paramyosin. Knowing what you know about the cellular mechanism of muscle contraction, propose a hypothesis to explain how paramyosin might

You know from experience that skeletal muscle tires quite quickly, especially if there is not enough oxygen. Interestingly, shellfish such as clams can maintain a month-long contraction in the muscle that keeps the shell closed. No oxygen gets in this situation. These muscles have a different version of myosin called paramyosin. Knowing what you know about the cellular mechanism of muscle contraction, propose a hypothesis to explain how paramyosin might

BIOLOGY:CONCEPTS+APPL.(LOOSELEAF)

10th Edition

ISBN:9781305967359

Author:STARR

Publisher:STARR

Chapter32: Structural Support And Movement

Section: Chapter Questions

Problem 2CT: After death, a person no longer makes ATP, so calcium stored in the sarcoplasmic reticulum diffuses...

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The _____ is the basic unit of muscle contraction. a. myofibril b. sarcomere c. muscle fiber d. myosin filament
After death, a person no longer makes ATP, so calcium stored in the sarcoplasmic reticulum diffuses down its concentration gradient into the muscle cytoplasm. This result is rigor mortis----an unbreakable state of muscle contraction that stiffens the body for a few days until muscles begin to decay. Explain why this contraction occurs.
Why do you think a person is able to perform anaerobic exercise (such as lifting and holding a heavy weight) only briefly but can sustain aerobic exercise (such as walking or swimming) for long periods? (Hint: Muscles have limited energy stores.)
What happens when myosin filaments hydrolyze ATP molecules in muscles? a. Actin–myosin complexes dissociate, leading to muscle contraction. b. Actin–myosin complexes dissociate, leading to muscle relaxation. c. Actin–myosin complexes are formed, leading to muscle contraction. d. Actin–myosin complexes are formed, leading to muscle relaxation.
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.
This thick filament motor protein composed of 6 polypeptide chains uses ATP hydrolysis to interact creating a powerstroke for skeletal muscle contractions. A Myosin B Actin C Titin D Tropomyosin
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.
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.
The role of tropomyosin in a muscle cell is to ____. all to cell to relax by blocking the binding sites on actin facilitate the formation of cross-bridges between actin and myosin Interactions between thick and thin filaments during muscle contraction occur in which sequence? "attach to actin, detach from actin, pivot in powerstroke, return or recock" "attach to actin, pivot in powerstroke, detach from actin, return or recock" "attach to actin, pivot in powerstroke, return or recock, detach from actin" "detach from actin,pivot in powerstroke, attach to actin, return or recock" What is the role of calcium pump in muscle contractions? pump calcium out of the sarcoplasmic reticulum against its concentration gradient to initiate contractions remove calcium from the fluid surrounding the myofibrils to end contractions pump calcium into the muscle cell to stimulate the release of acetylcholine
Which of the following statements best describes the sliding filament mechanism of muscle contraction? a. Actin and myosin filaments do not shorten, but rather, slide past each other. b. Actin and myosin filaments shorten and slide past each other. c. As they slide past each other, actin filaments shorten, but myosin filaments do not shorten. d. As they slide past each other, myosin filaments shorten, but actin filaments do not shorten.
What would happen to muscle function if you ingested a toxin that completely inactivated troponin? The toxin inhibits its ability to change conformation. How would this affect muscle contraction?
The mechanism of muscle contraction is best explained by the sliding filament model. According to this model, thin ___i___ filaments slide over thick ___ii___ filaments.The statement given above is completed by information in row Row i ii A. myosin actin B. myosin myosin C. actin actin D. actin myosin