Monovalents (e.g., `Na^(+),K^(+)`)_____membrane permeability while divalents (e.g., `Ca^(2+)`)_____the same.

Options

A. increase, decrease
B. decrease, increase
C. increase, increase
D. decrease, decrease

Answer

To answer the question regarding the effects of monovalent and divalent ions on membrane permeability, we can break down the solution into several steps:

### Step-by-Step Solution:

1. **Understand the Terms:**
- Monovalent ions (e.g., Na⁺, K⁺) have a charge of +1.
- Divalent ions (e.g., Ca²⁺) have a charge of +2.

2. **Membrane Permeability:**
- The plasma membrane is semi-permeable, meaning it allows certain substances to pass while restricting others.

3. **Effect of Monovalent Ions:**
- Monovalent ions are generally larger in size compared to divalent ions.
- Due to their larger size and lower charge density, monovalent ions tend to **decrease** membrane permeability.

4. **Effect of Divalent Ions:**
- Divalent ions are smaller and have a higher charge density.
- Their smaller size allows them to pass through the membrane more easily, which tends to **increase** membrane permeability.

5. **Conclusion:**
- Therefore, the correct completion of the statement is:
- Monovalents (e.g., Na⁺, K⁺) **decrease** membrane permeability while divalents (e.g., Ca²⁺) **increase** the same.

### Final Answer:
Monovalents (e.g., Na⁺, K⁺) **decrease** membrane permeability while divalents (e.g., Ca²⁺) **increase** the same.

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