Which of the following processes does not require ATP?
Membrane transport energetics divide conceptually into active requiring cellular energy input and passive driven solely by existing electrochemical gradients toward equilibrium. Primary active transport directly couples exergonic ATP hydrolysis to ion movement against gradient: Na+/K+ ATPase phosphorylates aspartate forming E1P E2P cycle extruding three sodium importing two potassium, V-type proton pumps rotate c-ring acidifying lysosomes using ATP, ABC transporters dimerize nucleotide binding domains consuming ATP to expel drugs and lipids. Secondary active cotransporters such as SGLT1 sodium
Ref: Lodish et al., Molecular Cell Biology, Chapter 11: Classification of Transport - ATP Requirement.
