Water fleas (Daphnia) and unicellular green algae (Chlorella) are placed in sealed vials containing a dilute pH indicator solution. Initially, the indicator is green at a neutral pH of 7.0.
- When dissolved carbon dioxide (CO2\text{CO}_2CO2) increases, it forms carbonic acid, decreasing the pH and turning the indicator yellow.
- When dissolved CO2\text{CO}_2CO2 decreases, the pH increases, turning the indicator blue.
The four vials are placed under a bright light source for 12 hours.
In which vial will the indicator turn the most blue (become the most alkaline)?
Vial 1
Vial 2
Vial 3
Vial 4
Respiration Questions
Practise OCR GCSE Biology Respiration with exam-style questions for Foundation and Higher tier. 29 questions, matched to the OCR GCSE Biology (J247) specification and written in the written papers style. Every question includes a full worked solution and mark scheme, so you can see where marks are awarded rather than just whether you got the answer right.