Which of the following functional groups is present in guanosine triphosphate ($\mathrm{GTP}$)?

• A. Phosphate group (${\mathrm{PO}}_4^\{3-\}$)
• B. Aldehyde group ($-\mathrm{CHO}$)
• C. Carboxyl group ($-\mathrm{COOH}$)
• D. Hydroxyl group ($-\mathrm{OH}$)

Answer: (A)

Verified step by step guidance

1. Begin by identifying the structure of guanosine triphosphate (GTP). GTP is a nucleotide composed of the guanine base, a ribose sugar, and three phosphate groups.
2. Recognize that the guanine base is a purine, which does not contain an aldehyde or carboxyl group. It has a complex ring structure with nitrogen atoms.
3. Examine the ribose sugar component of GTP. Ribose is a five-carbon sugar with hydroxyl groups attached to the carbon atoms, but it does not contain aldehyde or carboxyl groups.
4. Focus on the triphosphate part of GTP. This consists of three phosphate groups linked together, which is a key feature of GTP and distinguishes it from other nucleotides.
5. Conclude that the functional group present in GTP, based on its structure, is the phosphate group. This is the group responsible for the energy transfer properties of GTP in biochemical reactions.