What are the steps of the sliding filament model? Select all that apply. Sarcomeres are in a relaxed state, in which myosin-binding sites on actin are blocked. When a nervous signal excites the muscle, myosin-binding sites on actin open up and myosin binds to actin. The myosin heads hydrolyze ATP to ADP and P,. The binding of myosin to actin releases phosphate and triggers a power stroke. ATP binds to myosin, and the myosin releases its grip on actin, returning to a relaxed state.

What are the steps of the sliding filament model? Select all that apply. Sarcomeres are in a relaxed state, in which myosin-binding sites on actin are blocked. When a nervous signal excites the muscle, myosin-binding sites on actin open up and myosin binds to actin. The myosin heads hydrolyze ATP to ADP and P,. The binding of myosin to actin releases phosphate and triggers a power stroke. ATP binds to myosin, and the myosin releases its grip on actin, returning to a relaxed state.

Human Physiology: From Cells to Systems (MindTap Course List)

9th Edition

ISBN:9781285866932

Author:Lauralee Sherwood

Publisher:Lauralee Sherwood

Chapter8: Muscle Physiology

Section: Chapter Questions

Problem 2TAHL

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Figure 38.37 Which of the following statements about muscle contraction is true? The power stroke occurs when ATP is hydrolyzed to ADP and phosphate. The power stroke occurs when ADP and phosphate dissociate from the myosin head. The power stroke occurs when ADP and phosphate dissociate from the actin active site. The power stroke occurs when Ca2+ binds the calcium head.
The _____ is the basic unit of muscle contraction. a. myofibril b. sarcomere c. muscle fiber d. myosin filament
Choose the best description of how myosin and actin are arranged within the two types of protein filaments in myofibrils. a.) Actin makes up the think filaments, and myosin makes up the thin filaments. b.) Myosin makes up the think filaments, and actin makes up the thin filaments. c.) Myosin and actin are randomly interspersed in the think filaments but are absent from the thin filaments. d.) Myosin and actin overlap with each other to make up both the think and thin filaments.
When ADP and Pi are bound to myosin in the cross-bridge cycle... (MULTIPLE SELECT) A. There is no force production and myosin is not bound to actin B. There is no force production and myosin is bound to actin C. There is force production and myosin is not bound to actin D. If its smooth muscle, a second phosphate might be bound to the light chain E. The cross-bridge is in a state of rigor mortis F. There is force production and myosin is bound to actin
The sliding filament model depicts how myosin motors attached to actin lead to muscle contraction. This process proceeds in a precise series of events. Indicate which of the following shows the correct order of steps in the sliding filament model. Group of answer choices Myosin binds ATP; myosin tightly binds actin; power stroke; myosin releases actin Myosin binds GTP; myosin releases actin; power stroke; myosin tightly binds actin Actin binds ATP; power stroke; myosin tightly binds actin; actin releases ADP Actin binds ADP; myosin releases actin; power stroke; actin releases ADP
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
How does the cross-bridge result in thin filaments sliding over thick for contraction? Use key terms below and identify them on a diagram. cross-bridge formation (need Ca+2), power stroke, detachment (need ATP), reset myosin head
For relaxation to occur, A. calcium leaves the sarcoplasmic reticulum, and troponin binds calcium and blocks the binding sites on actin. B. calcium enters the myofibril, it detaches from myosin, and the binding sites on myosin become inactive. C. sarcoplasm calcium levels fall, calcium is removed from troponin, and tropomyosin blocks binding sites on actin. D. extracellular calcium levels fall, calcium is pumped into the myofibril, and tropomyosin slides away from actin.
Where is ATP's energy used during crossbridge cycling? A. When ATP attaches to myosin and causes myosin to pull on actin ("pull" step) B. When ATP attaches to myosin and causes myosin to attach to actin ("grab" step) C. When ATP splits and pushes myosin back into the "cocked" position ("reset" step) D. When ATP attaches to actin and causes actin and myosin to separate ("release" step)
Which of the following are correct Dynein head elongates like a lever arm. ATP hydrolysis detaches myosin from actin Myosin slides over both thick and thin actin filaments ATP hydrolysis drives change in conformation of the myosin head.
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.
In the process of muscle contraction, which of the following steps requires hydrolysis of ATP to complete? movement of myosin head, pulling the thin filament binding of myosin head to active site on actin resetting of the myosin head back to its ready position letting go of myosin head from the active site on actin sliding of tropomyosin causing exposure of actin