Fluidity of cell membranes in cold weather is maintained by

Options

A. Increaseing number fo phospholipids with unsaturated hydracarbon tails
B. Inceasing the proportion of integral proteins
C. Increaseing concentration of cholesterol in membrane
D. Increasing the number of phospholipids with saturated hydrocarbon tails

Answer

**Step-by-Step Solution:**

1. **Understanding Cell Membrane Structure**: The cell membrane is primarily composed of a bilayer of phospholipids. This bilipid layer is crucial for maintaining the fluidity of the membrane.

2. **Role of Cholesterol**: Cholesterol molecules are interspersed within the phospholipid bilayer. They play a significant role in modulating membrane fluidity, especially in varying temperatures.

3. **Impact of Cold Weather**: In cold temperatures, the fluidity of the cell membrane can decrease as the phospholipids tend to pack more closely together, leading to a more rigid membrane.

4. **Maintaining Fluidity**: To counteract the effects of cold weather, cells can increase the proportion of unsaturated fatty acids in their phospholipid bilayer. Unsaturated fatty acids have one or more double bonds, which create kinks in the fatty acid chains. These kinks prevent the fatty acids from packing tightly together, thus maintaining fluidity.

5. **Avoiding Saturated Fatty Acids**: Saturated fatty acids, which have no double bonds, can lead to a more rigid structure when incorporated into the membrane. Therefore, increasing unsaturated fatty acids is essential for maintaining membrane fluidity in cold conditions.

6. **Conclusion**: The fluidity of cell membranes in cold weather is maintained by increasing the number of phospholipids with unsaturated hydrocarbon tails.

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