Nucleic acid with catalytic activity are called

Options

A. Apoenzymes
B. Abzymes
C. Ribozymes
D. Isozymes

Answer

To answer the question "Nucleic acid with catalytic activity are called," we will analyze the options provided and determine which one correctly identifies the nucleic acid that possesses catalytic properties.

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks for a type of nucleic acid that has catalytic activity. Nucleic acids include DNA and RNA, but only certain types of RNA are known for their catalytic functions.

2. **Analyzing the Options**:
- **Option A: Apozyme**: This refers to the protein part of an enzyme, which requires a cofactor to be active. It does not relate to nucleic acids or catalytic activity. **(Incorrect)**

- **Option B: Abzyme**: Abzymes are antibodies that have catalytic activity. While they are related to proteins, they are not nucleic acids. **(Incorrect)**

- **Option C: Ribozyme**: Ribozymes are RNA molecules that have the ability to catalyze biochemical reactions, similar to the way enzymes do. This is directly related to the question as it refers specifically to nucleic acids with catalytic activity. **(Correct)**

- **Option D: Isozyme**: Isozymes are different forms of an enzyme that catalyze the same reaction but differ in amino acid composition. They are not nucleic acids. **(Incorrect)**

3. **Conclusion**: Based on the analysis, the correct answer is **Ribozyme** (Option C), as it specifically refers to RNA molecules that exhibit catalytic activity.

### Final Answer:
Nucleic acid with catalytic activity are called **Ribozymes**.

---