Answer:
There are many membrane forming lipids for microorganisms like bacteria. Most commonly, they are amphiphilic lipids such as glycerophospholipids.
In the scenario discussed in the question, more fatty acids having cis double bonds will be seen in the cell membrane of the bacterial culture whose temperature is shifted from 37 degrees Celsius to 10 degrees Celsius.
Unsaturated glycerophospholipid fatty acids will be found abundantly in the cell membrane.
Glycerophospholipids having shorter chains would increase in number and percentage.