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.

Q: Which is a false statement about skeletal muscle structure?a. A myofibril is composed of multiple…

A: Skeletal or Striated muscle- These are present on muscles that are associated with the skeleton.

Q: The binding of calcium to troponin will directly cause A. the hydrolysis of ATP B. the binding of…

A: Actin-binding proteins and calcium ions play an important role in muscle contraction and relaxation.

Q: The sliding filament mechanism describes the process during which: a. actin and myosin slide…

A: The muscles of the body serves main role in the movement of the body parts such as legs, arms and…

Q: A typical relaxed sarcomere is about 2.3 μm in length and contracts to about2 μm in length. Within…

A: The muscles fibers are composed of myofibrils and in turn myofibrils are composed of myosin and…

Q: f a muscle cell had very short T-tubules, how much tension would the muscle fiber create, relative…

A: T tubules or the transverse tubules are the extensions of the cell membrane that penetrate into the…

Q: Which of the following statements best describes the sliding filament mechanism of muscle…

A: Actin- It is the main component of thin filament in muscle fibre, cytoskletal protein. Myosin-motor…

Q: Which item is biggest? A. myosin head B. myofibril C. troponin D. sarcomere

A: Muscles are compact structures made up of highly tensile , strong, long, multinucleated cells called…

Q: During a concentric contraction of a skeletal muscle fiber, myofibrils a. lengthen. b. remain the…

A: Muscle fibers are composed of myofibrils. The myofibrils are made up of myosin and actin filaments…

Q: Motor neurons innervate muscle fibers at specialized synapses called_______ . The release of…

A: In “motor neurons”, the cell bodies are located in the spinal cord, motor cortex, or brainstem. The…

Q: Arrange the steps of muscle contraction in the correct order Myosin head forms cross bridge with…

A: Tissue comprises structurally and functionally similar cells. It is a level of organization in…

Q: Nervous stimulation of musclesa. occurs at a neuromuscular junction.b. results in an action…

A: Answer is d.)  All of these Correct.

Q: The function of Ca2+ in skeletal muscle contraction is toa. cause an allosteric change in myosin so…

A: Skeletal muscles are a special type of muscles made up of contractile tissue. They are a type of…

Q: What is the function of calcium in muscle contractions? to bind to troponin and change its…

A: Skeletal muscles are a special type of muscles made up of contractile tissue. They are a type of…

Q: During contraction, the bulk of calcium comes from:   A. sarcomere   B. sarcoplasm…

A: There are two questions. One question has been answered. To get the answer for the other question,…

Q: Which of the following choices is CORRECT? A Myofibrils extend the length of a muscle fibre B.…

A: In muscles the sarcomer is termed as the fundamental unit. The sarcomer helps in the contraction.…

Q: The function of ATP during muscle contraction is toa. cause an allosteric change in myosin so it…

A: ATP(adenosine triphosphate) causes an allosteric change on myosin so it detaches from actin and…

Q: Which of these statements about the molecular structure of myofilaments is true?a. Tropomyosin has a…

A: Tendons attach skeletal muscles to the bone. Numerous bundles which make up the skeletal muscle are…

Q: When sarcomeres contract during muscle contraction, which of the following occurs?   A. The myosin…

A: Sarcomeres contract during muscle contraction.

Q: Once the calcium binds, what happens next? The myosin binding sites become available so myosin binds…

A: Muscles contract" in a sequence of binding and delivering amid the sarcomere's two thick and thin…

Q: In relaxed muscle, the myosin-binding site on actin is blocked by ________. a. titin b. troponin c.…

A: Tropomyosin is known to block myosin-binding sites on actin molecules. It prevents the formation of…

Q: According to the sliding filament model, when muscles contract,a. sarcomeres shorten.b. myosin heads…

A: Answer is option e.

Q: Myosin's affinity for actin occurs Following the power stroke When myosin is energized When a new…

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Q: What might happen if skeletal muscle lacked tropomyosin?   A. The striation pattern would…

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Q: According to the sliding filament theory: a. The tension increases linearly as actin-myosin overlap…

A: Introduction : The sliding filament theory states that the myosin filaments which are thick…

Q: Describe the structure of myosin molecules and how theycombine to form a myosin myofilament

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Q: Repetitive stimulation of a skeletal muscle fiber will cause an increase in contractile strength…

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Q: Which protein has binding sites that the myofilament "head" is able to attach to? Select one: a.…

A: Answer1- d. actin When muscle contracts, the globular heads of the thick myosin filaments attach to…

Q: Myosin binds to actin, then bends. What is ATP needed for next? A. to pump the Ca++ “keys” back into…

A: D option is the correct statement.

Q: Experimenters can separate F-actin thin myofilaments frommyosin thick myofilaments. First they…

A: Muscle tissues can change their length in response to the stimulus.

Q: Which of the following is true when a muscle is at rest: calcium ions bind to the troponin complex…

A: Muscle contraction is the activation of tension-generating sites within muscle cells.

Q: - The sacromere is: a- A functional unit of the skeletal muscle b- The area between two intercalated…

A: Muscle cells, commonly known as myocytes, are the cells that makeup muscle tissue. There are three…

Q: Rigor mortis occurs following death because a. tropomyosin remains over the myosin binding sites of…

A: Introduction: Rigor mortis helps in assessing the time since death to determine if the body had been…

Q: Where is ATP's energy used during crossbridge cycling? A. When ATP attaches to myosin and causes…

A: Muscle cells are specific for contraction. It allows for motions and facilitates bodily processes…

Q: When a muscle fiber is stimulated with repeated stimuli, the contraction force is summed due to: a)…

A: INTRODUCTION Summation is that the . occurrence of additional twitch contractions before the…

Q: a. Ca2+ does not affect muscle force. b. The muscle cell eventually habituates to the level of Ca2+…

A: Structure of muscle cell A muscle cell consists of hundreds of fibers. A single fiber consists of…

Q: Explain why myosin II in a sarcomere can produced force only for that sarcomere contraction and not…

A: SARCOMERE   It is the basic structural and functional unit of muscle tissue. COMPONENTS: Each…

Q: 51- are links between the Filamentous F-actin of thin filaments and myosin heads of thick filaments.…

A: Introduction Muscle contraction is the activation of tension-generating sites within muscle cells,…

Q: 18. The binding of calcium to troponin will directly cause A. the hydrolysis of ATP B. the binding…

A: Troponins are a group of proteins that are found in the skeletal and muscle fibres of the heart. It…

Q: Which of these steps in the production of force by myosin is INCORRECT? The binding of ATP to the…

A: As per our honor code, we are authorized to answer one question at a time, since you have not…

Q: For the myosin head to form cross bridges with actin, it is necessary for to bind to actin. a)…

A: When calcium atoms bind to the globular molecules like my os in protein, they change shape and this…

Q: When a muscle fiber is stretched from 60% of its optimal length to Lo, what change or changes are…

A: INTRODUCTION When a muscle is stretched, some of its fibers lengthen, but other fibers may remain at…

Q: The transverse tubular system: A)speeds the transmission of an action potential down the length of a…

A: *Tansverse tubular system is a network of interconnecting rings that surrounds a myofibril. *It…

Q: Arrange the steps in the correct order to explain how a muscle fiber contracts.   Myosin and actin…

A: The movement of muscles in the body in response to a stimulus is so quick that it is difficult to…

Q: Smooth muscles relax when: a) myosin kinase phosphorylates the myosin head b) myosin phosphatase…

A: Smooth muscles relax when myosin phosphatase removes a phosphate group from myosin. (Option B is…

Q: In an isometric contraction, the muscle develops tension but does not: a.  Expend energy. b.…

A:

Q: A sarcomere contracts when a) Thin filaments (actin) slide b) Thick filaments (myosin) slide c) Thin…

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Q: During muscle contraction, the cross-bridge detaches when ________.a. the myosin head binds to an…

A: Muscles can change their length in the response to a stimulus.

Muscle Action

A change in the body or a bodily organ as a result of its functioning is referred to as an action. Muscle action can be defined as the specific movement of a bodily part generated by the contraction of a muscle. The muscle proteins actin and myosin are the important contractile proteins involved in muscle action. Muscle contraction, in addition to movement, serves several other important functions in the body, including posture, heat generation, and joint stability. Muscle contraction maintains posture, which includes standing and sitting.