All the given statement are true, except

Options

A. DNA is more stable the RNA because DNA contains 5 methyl uracil and deoxyribose
B. DNA replication is semi-conservation bidirectional and semi-discontinuous
C. Taylor proved semi-conservative replication of DNA by working on E. Coil bacteria
D. Klenow fragment' is a part of DNA polymerase.

Answer

To solve the question "All the given statements are true, except," we need to evaluate each statement provided in the options and identify the incorrect one.

### Step-by-Step Solution:

1. **Evaluate the First Statement:**
- **Statement:** "DNA is more stable than RNA because DNA contains 5-methyl uracil and deoxyribose."
- **Analysis:** This statement is misleading. DNA does not contain uracil; instead, it contains thymine (which can be referred to as 5-methyl uracil). However, the statement correctly identifies that DNA is more stable than RNA due to the presence of deoxyribose (which lacks the reactive 2' hydroxyl group present in ribose). Therefore, while the reasoning is somewhat flawed, the conclusion about stability is correct.
- **Conclusion:** This statement is **true** but confusingly worded.

2. **Evaluate the Second Statement:**
- **Statement:** "DNA replication is semi-conservative, bidirectional, and semi-discontinuous."
- **Analysis:** This statement is accurate. DNA replication is indeed semi-conservative (each new DNA molecule consists of one original and one new strand), bidirectional (replication occurs in both directions from the origin), and semi-discontinuous (the leading strand is synthesized continuously while the lagging strand is synthesized in fragments).
- **Conclusion:** This statement is **true**.

3. **Evaluate the Third Statement:**
- **Statement:** "Taylor proved semi-conservative replication of DNA by working on E. coli bacteria."
- **Analysis:** This statement is incorrect. While Taylor did provide evidence for semi-conservative replication, he did so using root tip cells of the Vicia faba plant, not E. coli. The experiment demonstrating semi-conservative replication in E. coli was conducted by Meselson and Stahl.
- **Conclusion:** This statement is **false**.

4. **Evaluate the Fourth Statement:**
- **Statement:** "Clino fragment is a part of DNA polymerase."
- **Analysis:** This statement is correct. The term "clino fragment" refers to a portion of DNA polymerase that retains certain enzymatic activities, specifically 5' to 3' polymerase activity and 3' to 5' exonuclease activity.
- **Conclusion:** This statement is **true**.

### Final Conclusion:
The only statement that is false is the third one regarding Taylor's work with E. coli. Therefore, the answer to the question is:

**Answer:** Taylor proved semi-conservative replication of DNA by working on E. coli bacteria (this statement is false).

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