Topics:
Animal Physiology, Animal Refresher
Match: Muscle Proteins and Their Roles
Match the column:
| TABLE-I | TABLE-II |
|---|---|
| 1) Troponin C | a) Thin muscle filament |
| 2) Troponin T | b) ATPase |
| 3) Myosin head | c) Distance between two Z-lines |
| 4) Actin | d) Tropomyosin |
| 5) Sarcomere | e) Calcium |
- 1-e, 2-d, 3-b, 4-a, 5-c — Correct Answer
- 1-e, 2-b, 3-d, 4-a, 5-c
- 1-a, 2-d, 3-b, 4-e, 5-c
- 1-e, 2-d, 3-b, 4-c, 5-a
Explanation:
Correct Answer: 1-e, 2-d, 3-b, 4-a, 5-c
Explanation of Each Match
- 1-e) Troponin C → Calcium: Troponin C is the calcium-binding subunit of the troponin complex. When calcium (Ca²⁺) is released from the sarcoplasmic reticulum during muscle excitation, it binds to Troponin C, initiating the conformational changes that allow muscle contraction.
- 2-d) Troponin T → Tropomyosin: Troponin T (T = Tropomyosin-binding) anchors the troponin complex to tropomyosin filaments on the thin filament. Its binding causes tropomyosin to shift, exposing myosin-binding sites on actin.
- 3-b) Myosin head → ATPase: The myosin head has ATPase activity — it hydrolyzes ATP (ATP → ADP + Pi) to generate the energy needed for the power stroke during muscle contraction. Without ATP, the cross-bridge remains locked (rigor mortis).
- 4-a) Actin → Thin muscle filament: Actin is the main component of the thin filament. It is a globular protein (G-actin) that polymerizes into filamentous actin (F-actin), forming the thin filament along with tropomyosin and troponin.
- 5-c) Sarcomere → Distance between two Z-lines: The sarcomere is the basic structural and functional unit of the myofibril. It is defined as the segment between two consecutive Z-lines (Z-discs). It contains one complete set of thick (myosin) and thin (actin) filaments.
