What this practice covers
These questions are drawn from past CIE 9700 Biology papers and filtered to transport of oxygen and carbon dioxide. 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.
Start practising practice questions →
What examiners see students get wrong here
These are the errors that cost marks on transport of oxygen and carbon dioxide, taken from our own topic notes. Read them before you practise and you will recognise the traps in the questions.
- Saying haemoglobin carries four oxygen atoms. It carries four molecules, so eight atoms.
- Reading a right shift as higher affinity. Right means lower affinity and easier release.
- Saying carbon dioxide binds to the haem group. Oxygen binds to haem; carbon dioxide binds to the amino groups of the protein.
- Saying the Bohr effect is caused by carbon dioxide directly. It works through the hydrogen ions produced from it.
- Saying fetal haemoglobin has a lower affinity so oxygen passes to it. It is higher.
Revise it first
If any of the above is unfamiliar, work through the notes before practising: Transport of oxygen and carbon dioxide revision notes.