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B1.2.3 Control in plants GCSE items that can be used to define successful outcomes for peer and self assessment activities • Assessment of practical work Using Exam pro items to support successful outcomes Students will be able to test their progress against learning outcomes using questions taken from past AQA GCSE examinations. Version 2.0 Copyright © AQA and its licensors. All rights reserved. A student grew a plant in an upright pot. She then put the pot in a horizontal position and left the plant in the dark for two days. Diagram 3 shows the potted plant after two days in the dark. Plant growing upright Plant put horizontal in the dark Version 2.0 Copyright © AQA and its licensors. All rights reserved. Plant after 2 days in the dark Explain fully why the plant responded in this way. ................................................................................................ ................. ................................................................................................ ................. ................................................................................................ ................. ................................................................................................ ................. ................................................................................................ ................. ................................................................................................ Version 2.0 Copyright © AQA and its licensors. All rights reserved. Gravity accept gravitropism / geotropism 1 caused redistribution of auxin / hormone to lower side of stem 1 these hormones stimulate growth of cells on the lower side of the stem only 1 so the stem grows upwards 1 [4] Version 2.0 Copyright © AQA and its licensors. All rights reserved. • B1.2.3 Control in plants June 2012 BL1HP Charles Darwin investigated tropisms in plants. Some students did an investigation similar to Darwin’s investigation. The students: • grew seeds until short shoots had grown • used black plastic to cover parts of some of the shoots • put the shoots in light coming from one direction • put boxes over the shoots to keep out other light. The diagrams show how the investigation was set up. • Two days later the students took off the black plastic covers and looked at the shoots. • The diagrams show the results. Version 2.0 Copyright © AQA and its licensors. All rights reserved. • B1.2.3 Control in plants June 2012 BL1HP (a) Give two variables that the students should control in this investigation. ........................................................................................................................................ ........................... ........................................................................................................................................ ........................... ........................................................................................................................................ ..........(2 marks) (b) Shoot A bent towards the light as it grew. Explain how. ........................................................................................................................................ ........................... ........................................................................................................................................ ........................... ........................................................................................................................................ ........................... ........................................................................................................................................ ........................... ........................................................................................................................................ ........................... Version 2.0 Copyright © AQA and its (4 marks) licensors. All rights reserved. (c) What conclusions can be drawn from the results about: (c) (i) the detection of the light stimulus .............................................................................................................................................. ........(1 mark) (c) (ii) where in the shoot the response to the light takes place. .............................................................................................................................................. ........(1 mark) Version 2.0 Copyright © AQA and its licensors. All rights reserved. B1.2.3 Control in plants June 2012 Mark scheme Version 2.0 Copyright © AQA and its licensors. All rights reserved.