Hydrogencarbonate indicator is red at a normal carbon dioxide concentration. It turns purple when the concentration decreases and yellow when the concentration increases. A student sets up three sealed tubes. Each tube contains red hydrogencarbonate indicator and one leaf. The table shows the results after 2 hours. Table
| Tube | Light conditions | Colour of indicator after 2 hours |
|---|---|---|
| 1 | bright light | purple |
| 2 | dim light | red |
| 3 | dark | yellow |
| Which statement explains the result in tube 2? |
The leaf neither photosynthesises nor respires in dim light.
The leaf photosynthesises and respires at the same rate in dim light.
The leaf photosynthesises but does not respire in dim light.
The leaf respires but does not photosynthesise in dim light.
117 exam-style questions on OCR GCSE Biology 1.4 Photosynthesis, covering 1.4.1 Photosynthesisers as biomass producers, 1.4.2 Factors affecting the rate of photosynthesis, and 1.4.3 Limiting factors in photosynthesis. Each one has a worked solution and a mark scheme showing where the marks go.