Which of the following is incorrect w.r.t junction and its fuction?

Options

A. Tight junction - Promotes leaking of substances across a tissue
B. Adhering junction -Keeps neighbouring cells together
C. Gap junction -connects the cytoplasm of adjoinig cells for rapid transfer of ions and small molecules
D. Gap junction - Faciliates the cells to communicate with each other

Answer

To determine which statement is incorrect regarding junctions and their functions, we can analyze each type of junction mentioned in the question.

### Step-by-Step Solution:

1. **Identify the Types of Junctions**:
- The junctions mentioned are tight junctions, adhering junctions, and gap junctions.

2. **Understand the Function of Tight Junctions**:
- Tight junctions are specialized connections between adjacent cells that prevent the leakage of substances between them. They create a barrier that maintains the integrity of the tissue by sealing the spaces between cells.

3. **Evaluate the Given Statement for Tight Junctions**:
- The statement claims that tight junctions "promote leaking of the substance across a tissue." This is incorrect because tight junctions actually prevent leakage.

4. **Understand the Function of Adhering Junctions**:
- Adhering junctions (or adherens junctions) are responsible for keeping neighboring cells together. They provide mechanical stability and support.

5. **Evaluate the Given Statement for Adhering Junctions**:
- The statement regarding adhering junctions is correct as they do keep neighboring cells together.

6. **Understand the Function of Gap Junctions**:
- Gap junctions allow for direct communication between adjacent cells by connecting their cytoplasm. They facilitate the rapid transfer of ions and small molecules.

7. **Evaluate the Given Statements for Gap Junctions**:
- The statements regarding gap junctions facilitating communication and allowing the transfer of ions and small molecules are correct.

8. **Conclusion**:
- The only incorrect statement is regarding tight junctions, which are said to promote leakage, while in reality, they prevent it. Therefore, the answer to the question is that the first option regarding tight junctions is incorrect.

### Final Answer:
The incorrect statement with respect to junctions and their function is that tight junctions promote leaking of substances across a tissue.

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