Humber Admissions Practice Test

What is the role of proteins embedded in the cell membrane?

1. To provide energy for the cell

2. To aid in cell division

3. To facilitate communication between cells

4. To enable selective permeability

The correct answer is: To enable selective permeability

Proteins embedded in the cell membrane play a crucial role in enabling selective permeability, which is the ability of the cell membrane to regulate what enters and exits the cell. These proteins serve several functions, including acting as channels or transporters that allow specific substances, such as ions or nutrients, to cross the membrane while keeping unwanted substances out. This selective barrier is vital for maintaining the appropriate internal environment of the cell, enabling it to function effectively and respond to changes in its external surroundings. In addition to facilitating transport processes, these proteins are also integral for cell signaling and communication. They can serve as receptors that bind to signaling molecules, allowing the cell to respond to various stimuli. While the other roles mentioned, such as providing energy or aiding in cell division, might be associated with cellular functions, they are not directly linked to the primary purpose of membrane proteins. Thus, the role of enabling selective permeability is fundamental to the function of proteins in the cell membrane.