What this practice covers
These questions are drawn from past CIE 9700 Biology papers and filtered to transport mechanisms. You answer, you find out immediately whether you were right, and you get the reasoning for the correct option and for each distractor. Wrong answers go to a mistakes locker so you can come back to exactly those.
Practice is free. You need an account only so your progress and your mistakes are still there next time.
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What examiners see students get wrong here
These are the errors that cost marks on transport mechanisms, taken from our own topic notes. Read them before you practise and you will recognise the traps in the questions.
- Saying water is pushed up the xylem by root pressure. It is pulled by transpiration.
- Confusing cohesion with adhesion. Cohesion is water to water; adhesion is water to the vessel wall.
- Putting lignin in the Casparian strip. It is suberin.
- Saying phloem transport is upward. It runs source to sink, in either direction.
- Saying mass flow requires ATP along the whole tube. ATP is used at loading; the flow follows a pressure gradient.
- Saying humidity increases transpiration. High humidity reduces the gradient and slows it.
Revise it first
If any of the above is unfamiliar, work through the notes before practising: Transport mechanisms revision notes.