Which functional group is primarily responsible for transferring energy among organic molecules?

• A. Amino group ($-\mathrm{NH}{2}_{}$)
• B. Carbonyl group ($>C=O$)
• C. Phosphate group (${\mathrm{PO}}_4-$)
• D. Hydroxyl group ($-\mathrm{OH}$)

Answer: (C)

Verified step by step guidance

1. Identify the functional groups listed: amino group (−NH\_2), carbonyl group (>C=O), phosphate group (PO\_4\^{−}), and hydroxyl group (−OH).
2. Recall the role of each functional group in biological and organic molecules: amino groups are involved in forming amines and proteins, carbonyl groups are key in aldehydes and ketones, hydroxyl groups are characteristic of alcohols, and phosphate groups are involved in energy transfer.
3. Understand that energy transfer in organic molecules, especially in biological systems, is primarily mediated by high-energy phosphate bonds, such as those found in ATP (adenosine triphosphate).
4. Recognize that the phosphate group (PO\_4\^{−}) is the functional group responsible for storing and transferring energy through the formation and breaking of phosphoanhydride bonds.
5. Conclude that among the options, the phosphate group is the functional group primarily responsible for transferring energy among organic molecules.