A molecule of ATP is structurally most similar to a molecule of

Options

A. RNA nucleotide
B. DNA nucleotide
C. Amino acid
D. RNA nucleoside

Answer

To determine which molecule is structurally most similar to ATP (adenosine triphosphate), we need to analyze the components of ATP and compare them with the options provided.

### Step-by-Step Solution:

1. **Identify the Structure of ATP**:
- ATP is composed of three main components:
- An adenine base (a nitrogenous base)
- A ribose sugar (a five-carbon sugar)
- Three phosphate groups (connected to the ribose sugar)

2. **Analyze the Options**:
- **RNA Nucleotide**: An RNA nucleotide consists of:
- A nitrogenous base (which can be adenine, guanine, cytosine, or uracil)
- A ribose sugar
- One or more phosphate groups (typically one in a nucleotide)
- **DNA Nucleotide**: A DNA nucleotide consists of:
- A nitrogenous base (adenine, guanine, cytosine, or thymine)
- A deoxyribose sugar (which is different from ribose)
- One or more phosphate groups
- **Amino Acid**: Amino acids are the building blocks of proteins and have a completely different structure, consisting of an amino group, a carboxyl group, and a side chain (R group).
- **RNA Nucleoside**: An RNA nucleoside consists of:
- A nitrogenous base
- A ribose sugar
- No phosphate group

3. **Compare ATP with Each Option**:
- **RNA Nucleotide**: Shares the adenine base, ribose sugar, and phosphate groups (though ATP has three, while a nucleotide typically has one).
- **DNA Nucleotide**: Contains a different sugar (deoxyribose) and has a different base (thymine instead of uracil).
- **Amino Acid**: Does not share any structural components with ATP.
- **RNA Nucleoside**: Lacks the phosphate group, making it structurally different from ATP.

4. **Conclusion**:
- The molecule that is structurally most similar to ATP is the **RNA nucleotide** because it contains the same adenine base, ribose sugar, and phosphate groups (though in different quantities).

### Final Answer:
A molecule of ATP is structurally most similar to a molecule of **RNA nucleotide**.

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