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Students conducted a large first-hand investigation into enzyme activity - HSC - SSCE Biology - Question 18 - 2015 - Paper 1
Question 18
Students conducted a large first-hand investigation into enzyme activity. The aim in the report is shown. Aim: To determine the optimum pH of four different enzyme... show full transcript
Worked Solution & Example Answer:Students conducted a large first-hand investigation into enzyme activity - HSC - SSCE Biology - Question 18 - 2015 - Paper 1
Step 1
How many independent variables were in this first-hand investigation?
Answer
In this investigation, the aim is to determine the optimum pH of four different enzymes. The independent variable is the pH level which is manipulated to observe its effect on enzyme activity. Since there are four enzymes being tested, each enzyme can be treated as a single independent variable affecting the outcome (optimum pH). Therefore, the number of independent variables in this investigation is 2: the pH (which varies) and the type of enzyme (as different enzymes can have different optimum pH levels).
Thus, the correct answer is (B) 2.