AS Level Biology A H020_H020-02_QS1.;This is the official Question paper for A level biology 2020 OCR paper 2 , I also have the biology paper 2 Marking scheme listed available for purchase.

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AS Level Biology A H020/02 Depth in biology Question Set 1 This study source was downloaded by 100000823250788 from CourseHero.com on 05-03-2021 21:58:22 GMT -05:00 https://www.coursehero.com/file... /89282100/AS-Level-Biology-A-H020-H020-02-QS1pdf/ This study resource was shared via CourseHero.com 1. Fig. 1.1 shows a student’s diagrams of two plant cells. Each cell was observed using a different type of microscope. The cells are not drawn to scale. (a) Fig 1.1 (i) Cell B in Fig. 1.1 was observed using an electron microscope. Give one piece of evidence from Fig. 1.1 that supports this. [1] (ii) Give one way that an image produced by a laser scanning confocal microscope differs from that produced by an electron microscope. [1] (b) Meiosis is a type of nuclear division. Fig. 1.2 shows a photomicrograph of plant cells undergoing meiosis. Fig. 1.2 This study source was downloaded by 100000823250788 from CourseHero.com on 05-03-2021 21:58:22 GMT -05:00 https://www.coursehero.com/file/89282100/AS-Level-Biology-A-H020-H020-02-QS1pdf/ This study resource was shared via CourseHero.com (i) Identify the stage of meiosis 1 shown in the cell labelled A. [1] (ii) Based only on your observations of Fig.1.2, state two reasons for your answer in (b)(i). [2] (iii) Another stage of meiosis is metaphase 1. Explain how the organisation of homologous chromosomes during metaphase 1 increases genetic variation. [3] (c) The use of stem cells is being evaluated for the treatment of certain human diseases. Name two potential sources of human stem cells and for one source, describe an ethical issue associated with the use of stem cells [Show More]

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