Which of the following are examples of passive transport?

• A. Endocytosis and exocytosis
• B. Facilitated diffusion
• C. Diffusion and osmosis
• D. Sodium-potassium pump

Answer: (C)

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 simple diffusion, facilitated diffusion, and osmosis.
3. Differentiate between passive and active transport: Active transport requires energy (usually in the form of ATP) to move substances against their concentration gradient, such as the sodium-potassium pump, endocytosis, and exocytosis.
4. Recognize examples of passive transport: Facilitated diffusion and osmosis are examples of passive transport. Facilitated diffusion involves the use of transport proteins to move substances across the cell membrane, while osmosis is the diffusion of water through a selectively permeable membrane.
5. Eliminate incorrect options: Endocytosis and exocytosis are forms of active transport, as they require energy to move large molecules or particles into or out of the cell. The sodium-potassium pump is also an active transport mechanism, as it moves ions against their concentration gradient using ATP.