What type of cellular transport does not require energy?

• A. Active transport
• B. Passive transport
• C. Facilitated diffusion
• D. Endocytosis

Answer: (B)

The type of cellular transport that does not require energy is indeed passive transport. This process involves the movement of molecules across a cell membrane along their concentration gradient, meaning substances move from an area of higher concentration to an area of lower concentration.

Passive transport occurs naturally without the need for energy input because it relies on the inherent kinetic energy of the molecules involved. For example, simple diffusion allows small and nonpolar molecules, such as oxygen and carbon dioxide, to pass freely through the lipid bilayer of the cell membrane without the assistance of proteins or the expenditure of ATP.

Additionally, facilitated diffusion, which is a subset of passive transport, also does not require energy. This process utilizes specific transport proteins to help larger or polar molecules traverse the membrane, but it still operates on the principle of moving molecules down their concentration gradient.

In contrast, processes like active transport and endocytosis do require energy. Active transport moves substances against their concentration gradient, which necessitates ATP, while endocytosis involves the engulfing of substances into the cell, also requiring energy to reorganize the cell membrane.