Explain active transport energetics
A membrane model in a advanced cell biology class shows ions moved against their concentration gradient through a pump while ATP is hydrolysed. Explain why ATP is required. Use the diagram labels, HL model, or quantitative image evidence before answering. Enter the answer and choose the interpretation that best matches the HL biological evidence.
Worked practice: biological evidence and answer
Use the labelled biological evidence first, then connect it to the final answer.
Write a full answer
Now write the response in full, in your own words — this is what the exam asks for. The AI marks it on the same moves you built above (focus, evidence, technique, judgement) and gives feedback on reasoning, evidence, and expression.