Question

which mechanism requires energy?

○ diffusion of oxygen into a red blood cell

○ osmosis

○ exocytosis

○ diffusion of ions through a potassium channel

Explanation:

• Diffusion of oxygen into a red blood cell: This is simple diffusion (passive transport), moving from high to low concentration, no energy needed.
• Osmosis: A type of passive transport (water movement across a semi - permeable membrane), no energy required.
• Exocytosis: It is a form of active transport where cells secrete substances (like proteins, hormones) by fusing vesicles with the plasma membrane. This process requires energy (usually in the form of ATP) to move substances against concentration gradients or for the vesicle fusion process.
• Diffusion of ions through a potassium channel: This is facilitated diffusion (passive transport), as ions move through a channel from high to low concentration, no energy is used.

Answer:

C. exocytosis