Biology and Combined Science (Biology part)
School-based Assessment Sample Tasks
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Hong Kong Examinations and Assessment Authority
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HKDSE Biology SBA
Practical Task:
Topic: I (e)
Presence of protease in pineapple and / or kiwifruit
Scenario:
Last week, Mary prepared some jelly for her mother’s birthday. In addition to plain jelly, she added fresh fruits into some of the jelly. She found that all the plain jelly set as usual, but jelly with fresh pineapple and fresh kiwi added failed to set. She was intrigued by this observation and she asked Miss Chan, her biology teacher, about it. Instead of telling Mary the answer directly, Miss Chan provided her with a piece of useful information: “Jelly contains a kind of protein called gelatin, which causes the jelly solution to solidify and set after cooling.”
Task:
Propose a hypothesis to explain Mary’s observation, i.e. jelly fails to set with the addition of fresh pineapple and kiwifruit. How would you design and carry out an investigation to test your hypothesis? Write a full report for your investigation
The following sections should be included in your report where applicable:
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Aim of your investigation
Introduction to your investigation report, which should include:
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Problem to investigate (refer to the description above)
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Hypothesis to explain the observation and the prediction based on the design of the investigation (where applicable)
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Principles behind the design of your investigation, which should include:
(i) a brief description of the rationale of your design;
(ii)
identification of the independent and dependent variables, and the ways of manipulating and measuring the variables;
(iii) the controlled variable(s); and
(iv) the critical assumptions made, if any.
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Procedure