Which of the following is nucleotide?

Options

A. Adenylic acid
B. Adenosine
C. RNA
D. Adenine

Answer

To determine which of the given options is a nucleotide, we need to understand the definition and structure of a nucleotide. A nucleotide consists of three components:

1. A nitrogenous base
2. A pentose sugar
3. A phosphate group

Now, let's analyze each option provided in the question:

### Step 1: Analyze Option A - Adenylic Acid
- **Structure**: Adenylic acid contains a phosphate group, a pentose sugar, and an adenine nitrogenous base.
- **Conclusion**: Since it has all three components, adenylic acid is a nucleotide.

### Step 2: Analyze Option B - Adenosine
- **Structure**: Adenosine consists of a pentose sugar and a nitrogenous base (adenine) but lacks a phosphate group.
- **Conclusion**: Since it is missing the phosphate group, adenosine is not a nucleotide; it is classified as a nucleoside.

### Step 3: Analyze Option C - RNA
- **Structure**: RNA is a polymer made up of multiple nucleotides linked together by phosphodiester bonds.
- **Conclusion**: RNA itself is not a single nucleotide; it is a sequence of nucleotides, thus it cannot be classified as a nucleotide.

### Step 4: Analyze Option D - Adenine
- **Structure**: Adenine is solely a nitrogenous base without a pentose sugar or phosphate group.
- **Conclusion**: As it lacks both the sugar and phosphate components, adenine is not a nucleotide.

### Final Conclusion:
The only option that qualifies as a nucleotide is **Option A - Adenylic Acid** because it contains a nitrogenous base, a pentose sugar, and a phosphate group.

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