Which of the following is not a type of passive transport?

• A. Endocytosis
• B. Osmosis
• C. Facilitated diffusion
• D. Diffusion

Answer: (A)

Verified step by step guidance

1. Understand the concept of passive transport: Passive transport is the movement of molecules across a cell membrane without the need for energy input from the cell. It relies on the concentration gradient, moving substances from an area of higher concentration to an area of lower concentration.
2. Identify the types of passive transport: The main types of passive transport include diffusion, osmosis, and facilitated diffusion. Each of these processes occurs without the use of cellular energy (ATP).
3. Define diffusion: Diffusion is the movement of molecules from an area of higher concentration to an area of lower concentration until equilibrium is reached. It is a fundamental type of passive transport.
4. Define osmosis: Osmosis is a specific type of diffusion that involves the movement of water molecules across a selectively permeable membrane from an area of lower solute concentration to an area of higher solute concentration.
5. Define facilitated diffusion: Facilitated diffusion is a process where molecules move across the cell membrane through protein channels or carriers, still moving down their concentration gradient without energy input. Recognize that endocytosis is an active transport process, requiring energy to move substances into the cell, thus not a type of passive transport.