Prelims 2013 · archive
MediumConsider the following minerals:
- 1.Calcium
- 2.Iron
- 3.Sodium
Which of the minerals given above is/are required by the human body for the contraction of muscles?
Answer & explanation
Answer: (d) 1, 2 and 3
All three minerals are needed. Calcium and sodium act in the signalling that triggers a muscle to contract. Iron is needed to make myoglobin, the muscle protein that stores the oxygen muscles use to produce energy for contraction.
- ✓ 1. Calcium is needed for squeezing and relaxing muscles. Calcium ions released inside muscle cells trigger the contraction.
- ✓ 2. The body needs iron to make myoglobin, the oxygen-carrying protein found in muscles. Myoglobin holds oxygen that muscle cells use to produce the energy for contraction.
- ✓ 3. Sodium acts like a chemical battery that powers nerve impulses and muscle contractions. Sodium rushing into a muscle cell creates the electrical impulse that sets off contraction.
Remember · Muscle contraction needs calcium (the trigger), sodium (the electrical signal) and iron (myoglobin for oxygen). Hence all three minerals are required.
Sources
- MedlinePlus (US National Library of Medicine): Calcium in diet ↗ “Sending and receiving nerve signals Squeezing and relaxing muscles Releasing hormones and other chemicals Keeping a normal heartbeat”
- MedlinePlus (US National Library of Medicine): Iron in diet ↗ “The human body needs iron to make the oxygen-carrying proteins hemoglobin and myoglobin. Hemoglobin is found in red blood cells. Myoglobin is found in muscles.”
- NIGMS (US National Institutes of Health): Pass the Salt – Sodium's Role in Nerve Signaling ↗ “it acts like a chemical battery that powers our nerve impulses and muscle contractions.”
Question: UPSC Civil Services (Preliminary) 2013, General Studies paper. Explanation: Minimalist IAS, checked 25 Oct 2026 (how we verify). ·