Pearson Edexcel Level 3 GCE,. Biology A (Salters Nuffield) Advanced Subsidiary PAPER 2: Development, Plants and the Environmen. 100% APPROVED COMPREHENSION.

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Answer ALL questions. Write your answers in the spaces provided. Some questions must be answered with a cross in a box . If you change your mind about an answer, put a line through the box and then... mark your new answer with a cross . 1 An electron microscope can be used to identify organelles in eukaryotic cells. (a) The photograph shows part of a eukaryotic cell. (i) Label the nucleolus on the photograph. (1) (Source: AL1379899 – Jose Luis Calvo / Shutterstock / PAL) (ii) The nucleolus is not found in prokaryotic cells because they (1) A do not contain DNA B do not have a nucleus C only contain RNA D only contain single-stranded DNA (iii) Explain why the nucleus cannot be observed at the end of prophase in a eukaryotic cell. (2) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... ....................................................................................................................................................................................................................................................................................*P67148A0328* Turn over 3 (b) Some plants use asexual reproduction to produce offspring. The graph shows how the mass of DNA changes in dividing cells. 0 Time / hours Mass of DNA per cell 12 24 36 48 (i) Mitosis is occurring between (1) A 0 and 12 hours B 12 and 16 hours C 16 and 20 hours D 24 and 36 hours (ii) Explain why DNA is replicated before mitosis begins. (2) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... ....................................................................................................................................................................................................................................................................................4 *P67148A0428* (iii) Explain how large numbers of cells with the same phenotype can be produced in a tissue. 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(Total for Question 1 = 9 marks)*P67148A0528* Turn over 5 BLANK PAGE6 *P67148A0628* 2 Plant-based products provide a sustainable alternative to oil-based plastics. In a single year, over 7600 million single-use plastic bags were given to customers by supermarkets in England. The mean mass of each bag was 5.5 g. (a) Calculate the total mass in kilograms of plastic bags given out to customers. Give your answer in standard form. (2) Answer .............................................................. k [Show More]

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