Nucleic acid was discovered as nuclein by:

Options

A. Miescher
B. Koch
C. Altemann
D. Flemming

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks who discovered nucleic acid, which was initially referred to as "nuclein."

2. **Identifying the Scientist**: The scientist who discovered nucleic acid as nuclein is Jonas Friedrich Mischer.

3. **Historical Context**: Mischer identified nuclein in 1869 while studying white blood cells (WBCs).

4. **Terminology**: At the time of his discovery, the term "nucleic acid" was not used; instead, he coined the term "nuclein" to describe the substance he observed.

5. **Significance of Discovery**: Mischer's work laid the foundation for the understanding of nucleic acids, which are essential for genetic information storage and transfer.

6. **Elimination of Other Options**:
- **Option B: Koch** - Robert Koch is known for discovering the cause of tuberculosis in 1882, not for nuclein.
- **Option C: Altman** - Richard Altman discovered mitochondria in the 1890s, not nuclein.
- **Option D: Fleming** - Alexander Fleming is famous for discovering penicillin, not nuclein.

7. **Conclusion**: Based on the information above, the correct answer to the question is **Option A: Mischer**.

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