Radish seedlings were grown in the light in two nutrient solutions. Solution P contained all the mineral ions needed by the seedlings. Solution Q was identical but contained no magnesium ions.
The seedlings in solution Q gained less dry mass.
Why did the seedlings in solution Q gain less dry mass?
The seedlings formed less chlorophyll, so their rate of photosynthesis fell.
The seedlings made fewer amino acids, so their protein production decreased.
The seedlings closed their stomata, so less carbon dioxide entered their leaves.
The seedlings absorbed less oxygen, so aerobic respiration in their roots decreased.
127 exam-style questions on OCR GCSE Biology 6.2 Feeding the human race, covering 6.2.1 Biological factors affecting food security, 6.2.2 Agricultural solutions to growing demand, 6.2.3 Selective breeding, 6.2.4 Genetic engineering, 6.2.5 Steps in genetic engineering, 6.2.6 Benefits and risks of gene technology in agriculture, and 6.2.7 Biotechnological solutions to growing demand. Each one has a worked solution and a mark scheme showing where the marks go.