Carrier-mediated and channel-mediated diffusion have this in common
A They are both dependent on activated enzymes in order to function
B. both methods will result in materials moving from an area of low concentration to an area of higher concentration until an equilibrium is reached
C. They both use a protein structure as a doorway to allow materials that can’t diffuse directly through the plasma mentirane to get ante or out of the cell.
D. they are both constructed out of cholesterol and dependent on sodium ions
E.They both use ATP to change the shape of the carrier proteins or channel proteins
The correct answer and explanation is :
The correct answer is: C. They both use a protein structure as a doorway to allow materials that can’t diffuse directly through the plasma membrane to get into or out of the cell.
Explanation (300 words):
Carrier-mediated and channel-mediated diffusion are both forms of facilitated diffusion, which is a type of passive transport. Passive transport means that substances move across the cell membrane without the use of cellular energy (ATP). Instead, these processes rely on the natural movement of particles from an area of higher concentration to an area of lower concentration, down their concentration gradient.
The key similarity between carrier-mediated and channel-mediated diffusion is that both use specific protein structures embedded in the cell membrane to transport substances that cannot easily pass through the lipid bilayer. These include ions, glucose, amino acids, and other polar or charged molecules.
- Channel-mediated diffusion involves channel proteins, which form pores or tunnels in the membrane. These channels are selective and may be gated, allowing ions or water to flow through only when certain conditions are met (e.g., voltage-gated or ligand-gated channels).
- Carrier-mediated diffusion involves carrier proteins, which bind to specific molecules on one side of the membrane. The binding causes a conformational (shape) change in the protein that transports the molecule across the membrane to the other side.
In both cases, no ATP is used, and enzymes are not required to activate the process. The proteins simply facilitate the diffusion of substances that cannot move through the hydrophobic core of the membrane on their own.
Therefore, option C is correct because it accurately identifies the shared feature: both mechanisms use membrane proteins to allow selective movement of substances across the membrane, helping maintain homeostasis in the cell.
