Chapter 6, Problem 2Q

Summary Introduction

To analyze:

The factors responsible for influencing the membrane fluidity apart from the temperature.

Given:

An experiment to comparatively study the fluidity and composition of cell membranes was conducted by the researchers. They maintained different animals like 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. They incubated these animals for several days and then extracted the membranes of the neuronal cells of all these animals.

Researchers added a fluorescent molecule to each of the extracted membranes and incubated these membranes at 20°C. Fluorescence was measured and a graph was plotted by them which indicated the 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, the 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.

Introduction:

Fatty acids present in the membrane can be saturated or unsaturated. Saturated fatty acids do not constitute double bond and have no scope of addition of any molecule. Unsaturated fatty acids are those which comprise of double or triple bonds that have scope of addition of molecules and help in increasing the fluidity of the membrane. In cold temperatures, the amounts of unsaturated fatty acids are high to prevent the membrane from getting frozen and death of the organism.