Chapter 7, Problem 7.1CR

In what ways are membranes crucial to life?

Summary Introduction

To explain: The importance of membrane that is crucial to life.

Concept introduction: Cell is the basic unit of life. All cells are bounded by the plasma membrane. Eukaryotic cell contain many organelles that perform specific functions. These include Golgi apparatus, mitochondria, nucleus, endoplasmic reticulum, chloroplasts, and lysosomes. They have well organized membrane-bound structures.

Explanation of Solution

The plasma membrane is crucial to life. Some of the features of a plasma membrane are mentioned below:

• Plasma membrane is made of phospholipid bilayer. It is hydrophobic in nature. Non-polar molecules easily dissolve in the plasma membrane and pass through it but polar or hydrophilic molecules require a channel protein to pass through plasma membrane. 
• Plasma membrane is crucial to maintain the membrane fluidity. The organism found in the hot region will contain more saturated fatty acid in the plasma membrane. This will allow the membrane to be less fluidic. Similarly, the organism found in the cold region will contain more number of unsaturated fatty acids. This will allow the membrane to be more fluidic because unsaturated fatty acid will not allow tight-stacking of fatty acids.
• Plasma membrane has pores that allow the gap junctions to maintain a cytoplasmic environment to the local cells. This is helpful for the cells to work in harmony.
• Plasma membrane separates the organelle environment with the cytoplasm. This is helpful to maintain a local environment for enzymatic actions.
• Plasma membrane contains membrane protein that helps in the signal transduction. This maintains the communication between the cell and a foreign body.