Check all that apply to smooth muscle contraction.Check All That ApplyIn smooth muscles, tropomyosin reveals the myosin-binding site on calmodulin. In smooth muscles, tropomyosin reveals the myosin-binding site on calmodulin.Calmodulin molecules when bound to calcium activate myosin kinase.Calmodulin molecules when bound to calcium activate myosin kinase.Cross-bridge cycling is slower in forming when compared to skeletal muscles.Cross-bridge cycling is slower in forming when compared to skeletal muscles.Smooth muscles contraction is stimulated by neurons and hormones.Smooth muscles contraction is stimulated by neurons and hormones.
Question
Check all that apply to smooth muscle contraction.Check All That ApplyIn smooth muscles, tropomyosin reveals the myosin-binding site on calmodulin. In smooth muscles, tropomyosin reveals the myosin-binding site on calmodulin.Calmodulin molecules when bound to calcium activate myosin kinase.Calmodulin molecules when bound to calcium activate myosin kinase.Cross-bridge cycling is slower in forming when compared to skeletal muscles.Cross-bridge cycling is slower in forming when compared to skeletal muscles.Smooth muscles contraction is stimulated by neurons and hormones.Smooth muscles contraction is stimulated by neurons and hormones.
Solution
The following statements apply to smooth muscle contraction:
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Calmodulin molecules when bound to calcium activate myosin kinase. In smooth muscle cells, calcium ions bind to calmodulin, a protein that is always present in the cytoplasm of these cells. The calcium-calmodulin complex then activates myosin light chain kinase (MLCK), an enzyme that phosphorylates myosin, enabling it to bind to actin and carry out contraction.
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Cross-bridge cycling is slower in forming when compared to skeletal muscles. The process of contraction in smooth muscle is slower than in skeletal muscle. This is because the phosphorylation of myosin by MLCK, which is necessary for cross-bridge formation and contraction, is a slower process than the direct binding of calcium to troponin in skeletal muscle.
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Smooth muscles contraction is stimulated by neurons and hormones. Smooth muscle contraction can be initiated by various stimuli, including autonomic nervous system activity and hormones. This is in contrast to skeletal muscle, which is primarily controlled by somatic motor neurons.
The statement "In smooth muscles, tropomyosin reveals the myosin-binding site on calmodulin" is not correct. In smooth muscle, tropomyosin does not block the myosin-binding sites on actin (as it does in skeletal muscle). Instead, the myosin heads in smooth muscle must be phosphorylated by MLCK to enable them to bind to actin and initiate contraction. Calmodulin does not have a myosin-binding site.
Similar Questions
Which of the following statements accurately describes the characteristics of human skeletal muscle contraction? A) Calcium ions bind to troponin, causing movement of tropomyosin and exposing the myosin binding sites on actin B) Calcium ions bind to troponin, causing movement of tropomyosin and exposing the actin binding sites for myosin C) Calcium ions bind to actin, causing movement of tropomyosin and exposing the myosin binding sites on actin D) Calcium ions bind to tropomyosin, causing movement of troponin and exposing the myosin binding sites for actin E) Calcium ions bind to tropomyosin, causing movement of troponin and exposing the actin binding sites for myosin
n order for muscle contraction to occur during exercise calcium must bind to which of the following proteins? troponin. tropomyosin. myosin. actin.
he following is a list of the events that occur during a muscle contraction.1. Myosin cross-bridges bind to the actin.2. The free myosin head splits ATP.3. Calcium ion is released from the sarcoplasmic reticulum.4. The myosin head pivots toward the center of the sarcomere.5. Calcium ion binds to troponin.6. The myosin head binds an ATP molecule and detaches from the actin.The correct sequence of these events isQuestion 10Select one:a.3, 5, 1, 2, 4, 6.b.1, 3, 5, 4, 6, 2.c.1, 4, 6, 2, 3, 5.d.3, 5, 1, 4, 6, 2.e.5, 1, 4, 6, 2, 3.
What is the name for the linkage that forms between actin and myosin during muscle contraction?
Some organs containing smooth muscle are capable of maintaining a constant contraction rhythm. How do they do this?Multiple choice question.They contain pacemaker cells.They respond to rhythmic stimulation by the endocrine system.They have intercalated disks.They contain calmodulin.
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