Answer:
The functions of cellular or plasma membranes are diverse. Key roles include controlling cellular transport and responding to signals or hormones.
Cellular Transport
The plasma membrane is comprised of a phospholipid bilayer that houses transmembrane proteins, resulting in a semi-permeable barrier. The transport of substances hinges on the molecules' characteristics, such as glucose and amino acids, required by pancreatic cells. These larger, uncharged molecules cannot freely traverse the membrane, so they depend on transmembrane proteins by binding to carrier proteins, a process called passive transport. In contrast, active transport involves the use of ATP to move molecules like Hydrogen against an electrochemical gradient.
Other forms of cellular transport include:
- Osmosis and diffusion
- Endocytosis
- Exocytosis
Cellular Signalling
The cell membrane can communicate with adjacent cells through complex proteins, which may function as receptors or markers.
Membrane Receptors
These receive signals from the extracellular environment, triggering internal processes. They respond to stimuli such as hormones and growth factors.
Membrane Markers
These enable cells to recognize one another and react accordingly, whether for necessary development, like in organ formation, or to identify a foreign entity.
