Pearson Edexcel Level 3 GCE/ Biology A (Salters Nuffield) Advanced PAPER 3: General and Practical Applications in Biology. 100% approved pass rate.

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Answer ALL questions. Write your answers in the spaces provided. 1 Plants can respond to and use light. The photograph shows a seedling starting to grow from a germinating seed. (a) Explain why th... e seedling needs a supply of magnesium ions. (2) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... ....................................................................................................................................................................................................................................................................................*P65462A0332* Turn over 3 (b) Describe the role of IAA (auxin) in the phototropic response of plants. (4 2 Acetylcholinesterase is an enzyme involved in regulating the transmission of nerve impulses across some synapses. (a) Acetylcholinesterase is found on the cell surface membranes of neurones and red blood cells. These acetylcholinesterase molecules have different primary structures. In humans, a single gene codes for acetylcholinesterase. (i) Explain how a single gene can give rise to acetylcholinesterase molecules with different primary structures. (2) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... ................................................................................................................................................... [Show More]

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