Question

A breeding program in the zoo was meant to increase the population of arctic wolf. The idea was to breed the animals in a structured facility, such as the San Diego zoo, then release the wolves back into the tundra regions of far northern Canada. As you know, changes in biological membrane composition take place when animals are moved to environments with very different temperatures.   

The winter average temperature in far northern arctic region of Canada is -34^oC. The average winter low temperature in San Diego is +14.1^oC.
i. What factors affect the fluidity of the wolves’ cell membranes,

ii. What changes might be expected in the fatty acid components of the lipids in the lipid bilayers of the cells of the extremities of the wolves being transferred from the San Diego zoo to the arctic regions of northern Canada?

Please fully explain your answer. Thank you.

Answer 1

I. The membrane fluidity of the wolves cell membrane depends on the amount of unsaturated fatty acids, cholesterol, fatty acids incorporated with phospholipids of varying length and saturation, chain length of fatty acids.

ii. After transferring the wolves from San Diego zoo to the Arctic regions of northern Canada which is much colder region than San Diego, there will be modifications and changes in the cell membrane to maintain the fluidity of membrane. The changes those will occur are lower chain length of the fatty acids will be incorporated more to membrane lipid because high chain length of fatty acids are responsible for high melting temperature i.e., fluidity will be achieved at higher temperature. So at lower temperatures low chain length will facilitate fluidity. Similarly the concentration and degree of unsaturated fatty acids in the membrane lipids will increase to a greater extent as it will lower the melting temperature so that membrane fluidity can be attained at lower temperatures of Arctic region.