A culture of microscopic algae is kept in bright light and supplied with carbon dioxide.
Which statement describes what happens to the hydrogen released during the first stage of photosynthesis in the algae?
It diffuses out of the algal cells as a gas along with the oxygen.
It is joined with carbon dioxide in the second stage to build glucose.
It is used in respiration to release energy for the algal cells.
It is converted directly into starch during the first stage.
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.