Final answer:
Primary active transport moves ions across a membrane and requires ATP, while secondary active transport does not directly require ATP and involves the movement of material due to electrochemical gradients.
Step-by-step explanation:
Two mechanisms exist for transporting small-molecular weight material and small molecules.
Primary active transport moves ions across a membrane and creates a difference in charge across that membrane, which is directly dependent on ATP.
Secondary active transport does not directly require ATP: instead, it is the movement of material due to the electrochemical gradient established by primary active transport.