Question 1
Multiple choiceHard1 markThe schematic shows solute transfer between equal-sized compartments and two interconversions of ATP. Which interpretation correctly describes the energy transfers?
Show answer and explanation
Answer: D. The solute moves from a compartment with fewer particles to an equal-sized compartment with more particles, so it moves against the concentration gradient and requires energy. At X, ATP is hydrolysed to ADP and phosphate, releasing energy that can drive this transport. At Y, ATP is synthesized from ADP and phosphate, which requires an energy input.
A: reverses the energy changes for both ATP hydrolysis and ATP synthesis.
B: correctly identifies energy release at X but reverses the energy requirement for ATP synthesis.
C: correctly identifies the energy input for ATP synthesis but treats ATP hydrolysis as requiring energy input.
Remember: ATP hydrolysis releases energy; ATP synthesis requires energy.