Correct Answer:
C. High-energy Phosphate Bond
The correct answer is High-energy Phosphate Bond. ATP (Adenosine Triphosphate) is the primary energy currency of the cell. It stores energy in its high-energy phosphate bonds, specifically between its second and third phosphate groups. When these bonds are broken (hydrolyzed), energy is released to power cellular activities. Among the options:
- Ionic Bond: Electrostatic attraction between ions, not the main energy storage bond in ATP.
- Hydrogen Bond: Weak bond important for molecular structure, not for energy storage.
- High-energy Phosphate Bond: Correct; this is the energy-storing bond in ATP.
- Covalent Bond: A general type of bond; while phosphate bonds are covalent, the specific term is "high-energy phosphate bond".
Therefore, the correct answer is "High-energy Phosphate Bond".