Vitamins and Minerals Practice Test 2026 – Comprehensive Exam Prep

Iron is essential for the formation of hemoglobin, which is the protein in red blood cells responsible for transporting oxygen throughout the body. Hemoglobin consists of four heme groups, and each heme contains an iron atom. This iron atom binds to oxygen, allowing red blood cells to carry it from the lungs to other tissues. Without adequate iron, the body cannot produce enough healthy hemoglobin, leading to conditions such as iron deficiency anemia, where the red blood cells are unable to transport sufficient oxygen, causing fatigue and weakness.

In contrast, while sodium and calcium play important roles in various physiological processes—sodium in fluid balance and nerve signal transmission, and calcium in bone health and muscle function—they do not directly contribute to hemoglobin formation. Cobalamin, also known as Vitamin B12, is crucial for red blood cell production and DNA synthesis; however, it does not constitute a part of hemoglobin itself. Instead, it supports the processes that lead to the production of red blood cells, but iron is the key mineral that forms the core of hemoglobin's structure.