What is the most important difference between active and passive transport? (A) Active transport requires energy input, passive transport does not - HSC - SSCE Biology - Question 14 - 2008 - Paper 1

(A) Active transport requires energy input, passive transport does not. This statement accurately reflects the fundamental difference, as active transport often involves the use of ATP to move molecules against their concentration gradient, while passive transport relies on the natural movement of molecules without energy input.

(B) Active transport occurs in animals, passive transport occurs only in plants. This is incorrect since active transport is present in both animal and plant cells, and passive transport occurs in both as well.

(C) Active transport does not use membranes, passive transport always uses membranes. This statement is misleading; both types of transport involve membranes, but they differ in energy requirements.

(D) Active transport occurs whenever an organism moves, passive transport does not involve movement of the organism. This is incorrect as well, as active transport is not solely dependent on organism movement.

Based on the evaluations, the correct answer is (A): Active transport requires energy input, passive transport does not.