Nucleotide is composed of

Options

A. Sugar
B. Phosphoric acid
C. Nitrogenous base
D. All the above.

Answer

To answer the question "Nucleotide is composed of," we need to break down the components of a nucleotide step by step.

### Step 1: Identify the Components of a Nucleotide
A nucleotide is the basic structural and functional unit of nucleic acids. It is composed of three main components:
1. **Nitrogenous Base**
2. **Sugar**
3. **Phosphoric Acid (Phosphate Group)**

### Step 2: Describe the Nitrogenous Base
The nitrogenous base can be classified into two categories:
- **Purines**: These include adenine (A) and guanine (G).
- **Pyrimidines**: These include cytosine (C), thymine (T) (found in DNA), and uracil (U) (found in RNA).

### Step 3: Describe the Sugar
The sugar component of a nucleotide can be:
- **Ribose**: This is the sugar found in RNA.
- **Deoxyribose**: This is the sugar found in DNA.

### Step 4: Describe the Phosphoric Acid
The phosphoric acid (or phosphate group) is essential for the structure of nucleotides. It contributes to the formation of the backbone of nucleic acids and is involved in energy transfer (as seen in ATP).

### Step 5: Conclusion
Given these components, we can conclude that a nucleotide is composed of:
- A nitrogenous base
- A sugar (either ribose or deoxyribose)
- A phosphoric acid

Therefore, the correct answer to the question is **"all of the above"** since all three components are essential parts of a nucleotide.