Question

A membrane's transition temperature is determined and found to stretch over a wide range of temperatures. The membrane also exhibits high stability and a reduced permeability similar to that in most mammals. What membrane component is responsible for these traits and how does it do it?

Answer 1

Cholesterol is the membrane component responsible for a membrane's transition temperature range, stability, and reduced permeability, acting as a buffer to temperature changes and aiding the membrane's organization.

Step-by-step explanation:

The membrane component responsible for maintaining stability, a wide range of transition temperatures, and reduced permeability in mammalian cells is cholesterol. Cholesterol plays a vital role in the cell membrane, acting as a buffer to control the fluidity.

It dampens the effects of temperature fluctuations, thus helping the membrane to stay functional across various temperatures.

At low temperatures, it prevents the membrane from becoming too rigid, and at high temperatures, it keeps the membrane from becoming too fluid.

This allows for an extended range of temperature tolerance and aids in maintaining cell integrity and coordinated chemical reactions.

Moreover, cholesterol also contributes to the organization of the membrane by forming lipid rafts, which are clusters of transmembrane proteins. These rafts are crucial for various cellular processes such as signaling.

Cholesterol's presence in cell membranes is a key factor that enables animals, especially homeothermic mammals and birds, to maintain a stable and functional cell membrane despite environmental temperature changes.