Which of the following is the correct sequence that describes the excitation and contraction of a skeletal muscle fiber? 1. Tropomyosin shifts and unblocks the cross-bridge binding sites. 2. Calcium is released and binds to the troponin complex. 3. The sarcoplasmic reticulum is depolarized when a wave of depolarization moves from the neuromuscular junction into the cell's interior by way of the transverse tubules. 4. The thin filaments are ratcheted across the thick filaments by the heads of the myosin molecules using energy from ATP. 5. An action potential in a motor neuron causes the axon to release acetylcholine, which depolarizes the muscle cell membrane at the neuromuscular junction. a. 1 β 2 β 3 β 4 β 5 b. 2 β 1 β 3 β 5 β 4 c. 3 β 4 β 2 β 1 β 5 d. 5 β 3 β 1 β 2 β 4 e. 5 β 3 β 2 β 1 β 4 All of the following statements about a true hormone are correct except: a. They can be modified amino acids, peptides or steroid molecules b. They are used to communicate between different organisms. c. They are carried by the circulatory system d. They elicit specific biological responses from target cells. e. All of the above are correct statements about hormones.
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Then, the sarcoplasmic reticulum is depolarized when a wave of depolarization moves from the neuromuscular junction into the cell's interior by way of the transverse tubules (3). Show moreβ¦
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Which of the following is not a type of muscle? A, Hyaline B. Cardiac C. Skeletal D. Smooth 2.For muscle contraction to occur, ______________ is released from the sarcoplasmic reticulum and binds with ____________ . A) sodium, tropomyosin B) calcium, troponin C) calcium, tropomyosin D) sodium, troponin 3) Match the function to the correct body system. A) Skeletal system B) Muscular System 1. Protects the brain, spinal cord and rib cage. 2. Maintains posture and joint stability 3. Heat production for temperature homeostasis 4. Stores minerals and lipids (fat) 4) Which type of muscle is involuntary, non-striated and found in the walls of hollow organs such as the intestines and blood vessels? Why is it important for body homeostasis that this type of muscle is involuntary?
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Match the following steps of muscle contraction with their proper sequence, starting with "1" being the first event to occur, "2" being the second event to occur, etc. a. Action potential arrives at axon terminal. b. Calcium enters axon terminal. c. Released calcium ions bind to troponin. d. Action potential spreads along sarcolemma and down t-tubules of muscle cell. e. Calcium ions trigger synaptic vesicles to open. f. Action potential in t-tubules causes SR to release stored calcium within muscle cells. g. Myosin pulls actin and then releases ADP. h. A new ATP binds myosin causing it to release actin and become re-energized for another round of contraction. i. Acetylcholine is released from synaptic vesicles. j. Sodium enters muscle cells causing an action potential on muscle cell membrane. k. Troponin changes shape, moving tropomyosin and exposing myosin-binding sites on actin. l. Myosin binds actin. m. Calcium channels open on axon terminal. n. Acetylcholine diffuses across synaptic cleft. o. Acetylcholine binds to receptors and opens sodium ion channels on muscle membrane.
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