What is the process called when particles move across the plasma membrane from an area of high concentration to an area of low concentration without the use of energy?

What is the process called when particles move across the plasma membrane from an area of high concentration to an area of low concentration without the use of energy?

• A. Active Transport
• B. Facilitated Diffusion
• C. Passive Transport
• D. Osmosis

Answer: (C)

The process where particles move across the plasma membrane from an area of high concentration to an area of low concentration without the use of energy is known as passive transport. This mechanism relies on the natural tendency of molecules to spread out and achieve equilibrium, which occurs spontaneously due to random molecular motion. In passive transport, substances can flow through the membrane by simple diffusion, where small molecules like oxygen and carbon dioxide pass directly through the lipid bilayer. Additionally, passive transport can also involve facilitated diffusion, where larger or polar molecules use specific transport proteins to cross the membrane. However, the key characteristic defining passive transport is that it does not require cellular energy (ATP) to move substances down their concentration gradient. Osmosis, while related, specifically refers to the movement of water across a selectively permeable membrane, and is considered a type of passive transport. Active transport is distinct from passive transport because it involves movement against the concentration gradient, requiring energy input.

The process where particles move across the plasma membrane from an area of high concentration to an area of low concentration without the use of energy is known as passive transport. This mechanism relies on the natural tendency of molecules to spread out and achieve equilibrium, which occurs spontaneously due to random molecular motion.

In passive transport, substances can flow through the membrane by simple diffusion, where small molecules like oxygen and carbon dioxide pass directly through the lipid bilayer. Additionally, passive transport can also involve facilitated diffusion, where larger or polar molecules use specific transport proteins to cross the membrane. However, the key characteristic defining passive transport is that it does not require cellular energy (ATP) to move substances down their concentration gradient.

Osmosis, while related, specifically refers to the movement of water across a selectively permeable membrane, and is considered a type of passive transport. Active transport is distinct from passive transport because it involves movement against the concentration gradient, requiring energy input.