1. Oxygen (O): Makes up about 65% of the human body by mass. It's essential for respiration, water formation, and numerous biochemical processes.
2. Carbon (C): Forms the backbone of all organic molecules, making up about 18% of the human body. It's crucial for energy storage, building proteins, and forming DNA and RNA.
3. Hydrogen (H): Makes up about 10% of the human body. It's found in water, carbohydrates, lipids, and proteins, and is vital for energy transfer and maintaining pH balance.
4. Nitrogen (N): Makes up about 3% of the human body. It's a key component of proteins, nucleic acids (DNA and RNA), and other essential molecules.
5. Calcium (Ca): Makes up about 1.5% of the human body. It's essential for bone and teeth formation, muscle contraction, nerve function, and blood clotting.
6. Phosphorus (P): Makes up about 1% of the human body. It's found in DNA, RNA, ATP (energy currency of cells), and phospholipids (components of cell membranes).
7. Potassium (K): Makes up about 0.25% of the human body. It's vital for nerve impulses, muscle contractions, and maintaining fluid balance.
8. Sulfur (S): Makes up about 0.25% of the human body. It's found in proteins and many coenzymes, playing a crucial role in enzyme activity.
9. Sodium (Na): Makes up about 0.15% of the human body. It's important for fluid balance, nerve impulses, and muscle contractions.
10. Chlorine (Cl): Makes up about 0.15% of the human body. It's a component of stomach acid and is involved in fluid balance.
While these are the most abundant, other elements like magnesium, iron, zinc, and trace amounts of many others are also essential for life, playing specific roles in different biological processes.
