Question

Which of the following statements is likely true about the initial decrease in membrane fluidity?

1) This is unlikely because membrane fluidity decreases as the temperature is lowered.
2) This is unlikely because membrane fluidity increases as the temperature is lowered.
3) This is likely because membrane fluidity increases as the temperature is lowered.
4) This is likely because membrane fluidity decreases as the temperature is lowered.

Answer 1

The initial decrease in membrane fluidity likely occurs due to a decrease in temperature, which causes saturated fatty acid tails to compress and rigidify the membrane structure.

Step-by-step explanation:

The initial decrease in membrane fluidity is likely because membrane fluidity decreases as the temperature is lowered. When temperatures drop, saturated fatty acid tails of phospholipids in the cell membrane compress against each other, creating a denser and more rigid membrane structure. Contrastingly, unsaturated fatty acid tails, with their kinks or bends, provide space that helps maintain membrane fluidity. Thus, to prevent solidification, organisms may increase the proportion of unsaturated fatty acids in their cell membranes in response to lower temperatures. This adaptation is crucial for maintaining the proper function of the cell membrane, particularly in cold environments where rigidity can lead to membrane rupturing.