Multiple choice general knowledge science & technology

The main constituent of hemoglobin is

  1. Chlorine

  2. Iron

  3. Calcium

  4. None of these
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Hemoglobin contains iron ions (Fe²⁺) in its heme groups, which bind to oxygen molecules in the lungs and release them in tissues. Each hemoglobin molecule can carry up to 4 oxygen molecules thanks to its 4 iron-containing heme groups.

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