ATP-Dependent Cellular Transport Mechanisms

Steps:

• Define phagocytosis as a form of endocytosis that engulfs large particles, requiring cellular energy.
• Define active transport as movement of molecules against their concentration gradient using carrier proteins.
• Define facilitated diffusion as passive movement down a concentration gradient via channel or carrier proteins.
• Determine ATP usage: phagocytosis and active transport expend ATP for energy, while facilitated diffusion does not.

Why A is correct:

• Phagocytosis and active transport both require ATP hydrolysis to provide energy for moving substances against gradients or for mechanical work, per cellular energy principles.

Why the others are wrong:

• B: Facilitated diffusion is passive and ATP-independent.
• C: Excludes active transport, which requires ATP.
• D: Excludes phagocytosis, which requires ATP for vesicle formation.

Final answer: A