Grade 9 Biological Molecules Past Paper Practice Question PDF

Grade 9 Topic: Biological molecules Subtopic: Test for reducing sugar (Benedict test ) Past paper practice question. 1. Glucose is a reducing sugar. Benedict’s solution is used to test for the presence of reducing sugar. (a) Describe how you would use Benedict’s solution to test for reducing sugar...

Grade 9 Topic: Biological molecules Subtopic: Test for reducing sugar (Benedict test ) Past paper practice question. 1. Glucose is a reducing sugar. Benedict’s solution is used to test for the presence of reducing sugar. (a) Describe how you would use Benedict’s solution to test for reducing sugar in a piece of potato. Include details of a safety precaution in your answer............................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................ Some students were given a 1.0% glucose solution and some distilled water. They diluted the glucose solution to produce five solutions of different concentrations. The students tested each of the solutions they had prepared with Benedict’s solution. The concentrations of the solutions and the results of their tests are shown in Table 1.1. The students also decided to test the distilled water with Benedict’s solution. (b) (i) Write the result of this test in Table 1.1. (ii) Explain why the students tested the distilled water................................................................................................................................................................................................................................................................................... (c) The students compared the colour of their solutions after the same length of time. State three other variables that the students should have controlled to make their results comparable. 1................................................................................................................................................ 2................................................................................................................................................ 3................................................................................................................................................ The students were then provided with a glucose solution X of unknown concentration which they tested with Benedict’s solution. The result was a yellowish-orange colour. (d) (i) Use Table 1.1 to suggest what the students may have concluded about the % concentration of glucose in solution X...................................................................................................................................................................................................................................................................................