An increase or decrease in temperature can significantly affect the fluidity of the cell membrane. The cell membrane is primarily composed of a lipid bilayer, which consists of phospholipids, cholesterol, and proteins. The fluidity of the cell membrane is crucial for its proper functioning, including the movement of substances in and out of the cell, cell signaling, and maintaining the cell's overall structure.1. Increase in temperature: When the temperature increases, the kinetic energy of the molecules in the cell membrane also increases. This causes the phospholipids to move more rapidly and further apart from each other, leading to an increase in membrane fluidity. This increased fluidity can be beneficial up to a certain point, as it allows for more efficient transport of substances across the membrane and better cell signaling. However, if the temperature increases too much, the membrane can become too fluid, which can compromise its structural integrity and potentially lead to cell damage or death.2. Decrease in temperature: When the temperature decreases, the kinetic energy of the molecules in the cell membrane decreases as well. This causes the phospholipids to move more slowly and pack more closely together, leading to a decrease in membrane fluidity. As the membrane becomes less fluid, the movement of substances across the membrane and cell signaling can become less efficient. If the temperature decreases too much, the membrane can become too rigid, which can also compromise its structural integrity and potentially lead to cell damage or death.In summary, the fluidity of the cell membrane is sensitive to changes in temperature. An increase in temperature generally increases membrane fluidity, while a decrease in temperature decreases fluidity. Maintaining an optimal temperature is crucial for the proper functioning of the cell membrane and overall cell health.