Answer:
Membrane transport proteins play a crucial role in enabling the inner function of cells by facilitating the movement of various molecules across the cellular membrane. These proteins are embedded within the lipid bilayer of the cell membrane and act as gatekeepers, controlling the passage of specific substances into or out of the cell.
There are two primary types of membrane transport proteins: channels and carriers.
1. Channels: Channel proteins form aqueous pores across the cell membrane, allowing ions and small molecules to move across the membrane by passive transport. These channels are often selective, meaning they only allow specific ions or molecules to pass through based on size, charge, or other properties. Channels are usually open or closed, depending on the presence or absence of certain signals or conditions.
2. Carriers: Carrier proteins, also known as transporters or permeases, facilitate the movement of molecules across the membrane by a process called facilitated diffusion or active transport. Unlike channels, carriers undergo a conformational change to transport molecules across the membrane. Facilitated diffusion occurs along the concentration gradient and does not require cellular energy, while active transport moves molecules against the concentration gradient and often requires the expenditure of energy in the form of ATP.
Step-by-step explanation: