Movement of Substances Across the Plasma Membrane

Front

What is the structure of the plasma membrane based on the fluid mosaic model?

Back

The plasma membrane consists of a phospholipid bilayer, proteins, cholesterol, glycoproteins, and glycolipids.

Front

What are the components of a phospholipid molecule?

Back

A phospholipid molecule has a hydrophilic (polar) head that attracts water and hydrophobic (nonpolar) tails that repel water.

Front

What is the role of cholesterol in the plasma membrane?

Back

Cholesterol makes the phospholipid bilayer stronger and more flexible, and it reduces permeability to water-soluble substances.

Front

What is selective permeability in the context of the plasma membrane?

Back

Selective permeability means that the plasma membrane allows certain molecules to pass through while preventing or limiting the movement of others.

Front

What are the functions of the plasma membrane?

Back

The plasma membrane provides nutrients, supplies oxygen, regulates solute concentration, maintains pH, maintains ion concentration gradient, eliminates toxic waste products, and secretes useful substances.

Front

What is the fluid mosaic model?

Back

The fluid mosaic model describes the plasma membrane as a dynamic and flexible structure where phospholipids and proteins move laterally within the layer.

Front

What types of proteins are found in the plasma membrane?

Back

The plasma membrane contains channel proteins and carrier proteins.

Front

What is the function of glycoproteins and glycolipids in the plasma membrane?

Back

Glycoproteins and glycolipids act as receptors for hormones, stabilize the membrane, and serve as antigens for cell identification.

Front

What is the significance of the movement of substances across the plasma membrane?

Back

Movement of substances is necessary to provide nutrients, supply oxygen, regulate concentrations, eliminate waste, and secrete useful substances.

Front

What is an impermeable membrane?

Back

An impermeable membrane does not allow any substances to diffuse through it, such as a polythene membrane.