AQA-BL2HP-QP-JUN14-CR - Centre Number For Examiners Use...

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BL2HP G/KL/103779/Jun14/E4 (Jun14BL2HP01) General Certificate of Secondary Education Higher Tier June 2014 Additional Science BL2HP Unit Biology B2 Biology Unit Biology B2 Tuesday 13 May 2014 9.00 am to 10.00 am For this paper you must have: a ruler. You may use a calculator. Time allowed 1 hour Instructions Use black ink or black ball-point pen. Fill in the boxes at the top of this page. Answer all questions. You must answer the questions in the spaces provided. Do not write outside the box around each page or on blank pages. Do all rough work in this book. Cross through any work you do not want to be marked. Information The marks for questions are shown in brackets. The maximum mark for this paper is 60. You are expected to use a calculator where appropriate. You are reminded of the need for good English and clear presentation in your answers. Question 2 should be answered in continuous prose. In this question you will be marked on your ability to: – use good English – organise information clearly – use specialist vocabulary where appropriate. Advice In all calculations, show clearly how you work out your answer. Centre Number Candidate Number Surname Other Names Candidate Signature For Examiner’s Use Examiner’s Initials Question Mark 1 2 3 4 5 6 7 TOTAL H A
2 Do not write outside the box (02) G/Jun14/BL2HP Answer all questions in the spaces provided. 1 Some students investigated the effect of pH on the digestion of boiled egg white by an enzyme called pepsin. Egg white contains protein. The students: put a glass tube containing boiled egg white into a test tube added a solution containing pepsin at pH 7 set up six more tubes with solutions of pepsin at different pH values left the test tubes for 24 hours at room temperature. Figure 1 shows one of the test tubes, at the start and at the end of the 24 hours. Figure 1 24 hours 24 hours later At start Solution of pepsin 50 mm Boiled egg white Glass tube 1 (a) (i) Name the product of protein digestion. [1 mark] ............................................................................................................................................ 1 (a) (ii) What type of enzyme digests protein? Tick ( ) one box. [1 mark] amylase lipase protease
3 Do not write outside the box (03) G/Jun14/BL2HP Turn over 1 (b) The egg white in each tube was 50 mm long at the start of the investigation. Table 1 shows the students’ results. Table 1 pH Length in mm of boiled egg white after 24 hours 138 220 334 445 550 650 750 1 (b) (i) At which pH did the pepsin work best? [1 mark] pH .................................. 1 (b) (ii)

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