Vesicular Transport Alters Concentrations Unequally

Steps:

• Recall endocytosis engulfs external substances into the cell, increasing internal concentration relative to outside.
• Recall exocytosis releases internal substances to the exterior, increasing external concentration relative to inside.
• Determine that these processes allow movement against gradients, enabling either higher inside or higher outside concentrations.
• Match to options: B captures both possibilities for endocytosis (greater inside) or exocytosis (greater outside).

Why B is correct:

• By definition, endocytosis and exocytosis are active vesicular transports that move substances independent of concentration gradients, allowing relative concentrations to be greater inside or greater outside.

Why the others are wrong:

• A: Assumes equal concentrations, but these processes create imbalances, not equilibrium.
• C: Includes "equal" and repeats "greater outside," ignoring endocytosis's potential to increase inside.
• D: Vague phrasing with "or lower outside" fails to specify clear relative changes for both processes.

Final answer: B