Final answer:
Channel proteins in cell membranes allow the selective transport of ions across the lipid bilayer, while carbohydrates attached to the membrane enable cell recognition and communication, critical for immune responses and cellular interactions.
Step-by-step explanation:
Channel proteins and carbohydrates have distinct but essential roles in the functioning of cell membranes. Channel proteins, such as aquaporins and ion channels, provide specific pathways for substances to diffuse across the cell membrane. These proteins allow for the selective transport of molecules like sodium or potassium ions, which cannot easily pass through the lipid bilayer due to their charge.
On the other hand, carbohydrates attached to the plasma membrane play a crucial role in cell recognition. They form unique patterns attached to proteins or lipids, creating glycoproteins and glycolipids that enable cells to identify and interact with each other. This recognition is vital for immune responses, as it allows the body to differentiate between 'self' and 'non-self' entities like viruses that can alter their glycoprotein and glycolipid structures to evade detection.
In conclusion, each component of the cell membrane has a specialized function, from maintaining the internal environment with transport proteins to facilitating cell communication and recognition through carbohydrate chains.