On which surface of cell Donnan equilibrium occur
" " Or
Demosome is a modification of

Options

A. cellwall
B. plasma membrane
C. Transport
D. Nuclear membrane

Answer

**Step-by-Step Solution:**

1. **Understanding Donnan Equilibrium:**
- Donnan equilibrium refers to the distribution of ions across a semipermeable membrane that separates two solutions with different concentrations of ions. It occurs when there is a difference in the concentration of permeable ions on either side of the membrane.

2. **Identifying the Surface of the Cell:**
- In the context of cells, the semipermeable membrane is typically the plasma membrane. This membrane regulates the movement of ions and molecules in and out of the cell.

3. **Conclusion about Donnan Equilibrium:**
- Therefore, Donnan equilibrium occurs on the surface of the cell that is represented by the plasma membrane.

4. **Understanding Desmosomes:**
- Desmosomes are specialized structures that provide adhesion between cells. They are often referred to as "macula adherens" and are important for maintaining the structural integrity of tissues.

5. **Identifying the Modification:**
- Desmosomes are modifications of the plasma membrane, as they involve proteins that connect adjacent cells and provide mechanical stability.

6. **Final Answer:**
- The correct answers to the questions are:
- Donnan equilibrium occurs on the plasma membrane.
- Desmosomes are a modification of the plasma membrane.