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
Question
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
Solution
The correct answer is A) Calcium ions bind to troponin, causing movement of tropomyosin and exposing the myosin binding sites on actin.
Here's why:
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When a muscle contracts, the nervous system sends a signal to the muscle cells, which triggers the release of calcium ions from the sarcoplasmic reticulum, a structure within the muscle cell.
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These calcium ions then bind to a protein called troponin, which is located on the actin filament in the muscle cell.
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The binding of calcium to troponin causes a conformational change in another protein called tropomyosin, which is wrapped around the actin filament.
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This movement of tropomyosin exposes the myosin binding sites on the actin filament.
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Myosin heads, which were previously blocked by tropomyosin, can now bind to these exposed sites on the actin filament, leading to muscle contraction.
So, the statement A accurately describes the process of muscle contraction.
Similar Questions
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.
During contraction of a muscle, calcium ions bind to ______ which moves _______ out of the way. This now uncovers binding sites on the __________ myofilament. multiple choice 1troponin; tropomyosin; myosintroponin; tropomyosin; actintropomyosin; troponin; myosintropomyosin; troponin; actin 2. What molecules are attached to the myosin head from the previous cycle of movement? multiple choice 2ATP and phosphateADP and phosphateATP and calcium ionsADP and calcium ions 3. What is released in the process of cross-bridge formation? multiple choice 3ADPPhosphateATPCalcium ions 4. When the myosin head is moved, what is released (from the myosin head)? multiple choice 4ATPADPPhosphateCalcium ions 5. After the myosin head returns to its upright position, what occurs if calcium ions are still present? multiple choice 5Actin myofilaments move away from the M line.The entire sequence is repeated.Troponin blocks the binding sites on actin.Myosin heads will no longer bind to actin.
When calcium ion binds to troponinQuestion 9Select one:a.active sites on the myosin are exposed.b.muscle relaxation occurs.c.myosin shortens.d.tropomyosin moves into the groove between the helical actin strands.e.actin heads will bind to myosin.
During skeletal muscle contraction, calcium binds to Blank______.Multiple choice question.ATPtropomyosintroponinactin
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