Question 13
IGCSE_MODEL_QUESTIONS_VOL1
•
2022
•
BIOLOGY
•
objective
When a skeletal muscle fibre receives a single action potential, outline the sequence of events that leads to contraction, highlighting the role of the sarcoplasmic reticulum and troponin.
Answer Options
A.
Action potential → T‑tubule depolarisation → Ca²⁺ release from sarcoplasmic reticulum → Ca²⁺ binds troponin, moving tropomyosin → actin binds myosin and the cross‑bridge cycle ends.
B.
Action potential → T‑tubule depolarisation → Ca²⁺ release from sarcoplasmic reticulum → Ca²⁺ binds tropomyosin, moving troponin → myosin binds actin and the cross‑bridge cycle begins.
Correct Answer
C.
Action potential → T‑tubule depolarisation → Ca²⁺ release from sarcoplasmic reticulum → Ca²⁺ binds troponin, moving tropomyosin → myosin binds actin and the cross‑bridge cycle begins.
D.
Action potential → T‑tubule depolarisation → Na⁺ release from sarcoplasmic reticulum → Na⁺ binds troponin, moving tropomyosin → myosin binds actin and the cross‑bridge cycle begins.
Correct Answer
C
Correct Option:
Action potential → T‑tubule depolarisation → Ca²⁺ release from sarcoplasmic reticulum → Ca²⁺ binds troponin, moving tropomyosin → myosin binds actin and the cross‑bridge cycle begins.
About This Question
This is
Igcse Model Questions Vol1
2022
Biology
Question 13.
It is one of the
objective
questions from the
2022
Igcse Model Questions Vol1
Biology
examination.
Difficulty level:
Medium
.