Chapter 6, Problem 3Q

Summary Introduction

To analyze:

The process by which unsaturation affects the membrane fluidity.

Given:

Introduction:

The saturated fatty acids have no scope of addition of any molecule due to the presence of double bonds. The unsaturated fatty acids increase the membrane fluidity. In cold temperatures, the amounts of unsaturated fatty acids are high to prevent the membrane from damaging leading to the death of the organism. An experiment to comparatively study the fluidity and composition of cell membranes was conducted by the researchers. They maintained arctic sculpin at 0°C, a group of goldfish at 5°C, other group of goldfish at 25°C, desert pupfish at 34°C, and rats at normal temperature of 21°C and incubated them for several days. Researchers then extracted the membranes of the neuronal cells of all these animals.

A fluorescent molecule to each of the extracted membranes was added and the membranes were incubated at 20°C. Fluorescence was measured and a graph was plotted by them, which indicates fluorescence against the body temperature of each of the animals.

The following graph depicted the fluorescence of each animal at different temperatures. The more the value of fluorescence, less will be the movement of molecules depicting a less fluid membrane.

The following table was drawn by the researchers showing the ratio of saturated to unsaturated fatty acids in the phospholipid phosphatidyl choline for different animals taken into consideration.