What is the biological important of `Na^(+) and K^(+)` ions in cell fluids like blood plasma?

Options

A. They participate in transmission of nerve signals.
B. They regulate the number of red and white blood corpuscles in the cell
C. They ca be presence in any amount in the blood since they are absorbed by the cells.
D. They regulate the viscosity and colour of the blood

Answer

### Step-by-Step Text Solution

1. **Understanding Blood Plasma**: Blood plasma is the liquid component of blood that remains after the cellular components (like red blood cells, white blood cells, and platelets) have been removed. It contains water, electrolytes, nutrients, hormones, and waste products.

**Hint**: Recall that blood plasma is the fluid part of blood, essential for transporting substances throughout the body.

2. **Location of Sodium and Potassium Ions**: Sodium ions (Na⁺) are primarily found in the interstitial fluid, which is the fluid surrounding cells. In contrast, potassium ions (K⁺) are predominantly located inside the cells, particularly in the cytoplasm.

**Hint**: Remember the distinction between where sodium and potassium are found in relation to cell membranes.

3. **Functions of Sodium and Potassium Ions**:
- **Transmission of Nerve Signals**: Both Na⁺ and K⁺ are crucial for the generation and propagation of electrical signals in neurons. They help in depolarization and repolarization of the nerve cell membrane.
- **Regulation of Water Flow**: These ions help regulate osmotic balance and the flow of water across cell membranes. This is vital for maintaining cell shape and function.
- **Sodium-Potassium Pump**: This is a specific protein in the cell membrane that actively transports Na⁺ out of the cell and K⁺ into the cell, which is essential for maintaining the electrochemical gradient across the membrane.
- **Transport of Nutrients**: Sodium ions assist in the transport of sugars and amino acids into the cells through co-transport mechanisms.

**Hint**: Focus on the roles of Na⁺ and K⁺ in nerve function, water regulation, and nutrient transport.

4. **Activation of Enzymes**: Sodium and potassium ions are also involved in activating certain enzymes and biocatalysts, which play a role in various biochemical reactions within the body.

**Hint**: Consider how ions can influence biochemical processes and enzyme activity.

5. **Evaluating Options**: When considering the biological importance of Na⁺ and K⁺, the correct statement is that they participate in the transmission of nerve signals. Other options regarding regulation of blood corpuscles and viscosity are incorrect.

**Hint**: Analyze each option carefully to determine which accurately reflects the roles of sodium and potassium ions.

### Conclusion
The biological importance of sodium and potassium ions in blood plasma is primarily related to their roles in nerve signal transmission, regulation of water movement across cell membranes, and their involvement in various cellular processes, including enzyme activation.