What is not true w.r.t. the conditions associated with DNA entry into the host cell?

Options

A. DNA cannot pass through the cell membrane di- rectly on its own
B. DNA is hydrophilic in nature
C. `Ca^(2)` ions helps in entry of DNA into the host cell
D. Heat shock completely blocks the entry of DNA into the host cell

Answer

To solve the question regarding which statement is not true with respect to the conditions associated with DNA entry into the host cell, we can analyze each option provided in the question.

### Step-by-Step Solution:

1. **Understand the Question**: The question asks us to identify the statement that is not true regarding the conditions for DNA entry into a host cell.

2. **Analyze Each Option**:
- **Option 1**: "DNA cannot pass through the cell membrane directly on their own."
- This statement is **true**. DNA is a large, hydrophilic molecule and cannot easily cross the lipid bilayer of the cell membrane without assistance.

- **Option 2**: "DNA is hydrophilic in nature."
- This statement is also **true**. DNA has a sugar-phosphate backbone that is hydrophilic, making it unable to pass through the hydrophobic core of the cell membrane without help.

- **Option 3**: "Calcium ion helps in the entry of DNA into the host cell."
- This statement is **true**. Calcium ions can facilitate the entry of DNA into host cells by promoting the formation of pores in the cell membrane during certain methods of transformation.

- **Option 4**: "Heat shock completely blocks the entry of the DNA into the host cell."
- This statement is **not true**. The heat shock method actually promotes the entry of DNA into the host cell by creating pores in the membrane, allowing DNA to enter.

3. **Conclusion**: The statement that is not true regarding the conditions associated with DNA entry into the host cell is **Option 4**.

### Final Answer:
The correct answer is **Option 4**: "Heat shock completely blocks the entry of the DNA into the host cell."

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