BIOLOGICAL MOLECULES & MOVEMENT INTO AND OUT OF CELLS 2025 BIOLOGY Grade 10 Name and Surname Centre Number ZA331 Date [ 65 minutes ] INSTRUCTIONS: - Read your questions carefully. Answer all questions. Circle only one answer in pencil for multiple choice questions. If you make a mistake clearly erase the pencil. Write your answer to each question in the space provided. You should show all your work on the question paper. INFORMATION - The total mark for this paper is 65 marks. The number of marks for each question or part question is shown in brackets [ ]. This document consists of 21 printed pages. ______________________________________________________________________________ RUIMSIG ACADEMY is a registered Cambridge International School Centre Number ZA331 1 11 12 13 14 15 16 16 17 18 19 1 THEORY QUESTIONS 1 Plants can make glucose and proteins. Using the words from the list, complete the table to show all of the chemical elements that are found in glucose and all proteins. Each word may be used once, more than once or not at all. carbon hydrogen oxygen nitrogen magnesium glucose all proteins [2] [Total: 2] 2 2 Dialysis tubing is an artificial membrane, which is similar to the lining of the intestine. A student investigated the diffusion of glucose through dialysis tubing by using the apparatus shown in the diagram. The student took samples of the water outside the dialysis tubing at 5 minute intervals and tested the samples with Benedict’s solution. The results are shown in the table. time / minutes results of the Benedict’s tests on the water outside the dialysis tubing 0 blue 5 green 10 yellow 15 red Describe and explain the results shown in the table. .................................................................................................................................................. .................................................................................................................................................. .................................................................................................................................................. .................................................................................................................................................. .................................................................................................................................................. .................................................................................................................................................. .................................................................................................................................................. [3] [Total: 3] 3 3 This question is about biological molecules. Choose words or phrases from the list to complete the sentences. Each word or phrase may be used once, more than once, or not at all. calcium carbon cellulose chloroplasts glycogen oxygen carbon dioxide carbohydrate fat glycerol iron methane nitrogen protein starch Fats are composed of the elements .............................................. , hydrogen and .............................................. only. All proteins contain these three elements and the element ............................................. . Glucose is a type of ............................................... . Animals store excess glucose as .............................................. in the liver. Plants store excess glucose as .............................................. . Plants also convert glucose to .............................................. which is used to make cell walls. [7] 4 [Total: 7] 4 Starch is broken down into reducing sugars in the alimentary canal. The digested products are absorbed into the blood. Some students investigated the action of enzymes on the digestion of starch. Describe how you would carry out a test for starch. .................................................................................................................................................. .................................................................................................................................................. [2] [Total: 2] 5 In an investigation, students kept unripe bananas at room temperature for eight days. They studied some of the changes during ripening. Each day the students took one banana and: • • observed the colour of the banana skin; removed a sample of the flesh tissue and estimated the reducing sugar content. The table below shows the students' results. time / days (a) (i) change during ripening skin colour reducing sugar content / % 1 green 5 2 green and yellow 12 3 mostly yellow 18 4 all yellow 25 5 all yellow 30 6 yellow, some brown 29 7 yellow and brown 30 8 mostly brown 30 Suggest on which day the bananas became ripe. State one reason for your answer. day.......................................................................................................................... reason.................................................................................................................... ................................................................................................................................ [2] 5 (ii) The reducing content increased as the banana ripenend. Calculate how many times greater was the sugar content on day 5 compared with day 1. Show your working. ........................... [2] (iii) Suggest the source of the reducing sugar. ................................................................................................................................ ................................................................................................................................ [1] [Total: 5] 6 Describe how you would safely carry out a test for reducing sugars. .................................................................................................................................................. .................................................................................................................................................. .................................................................................................................................................. .................................................................................................................................................. .................................................................................................................................................. .................................................................................................................................................. [3] [Total: 3] 7 8 9 10 11 12