Check your understanding 1. Observe your agar plate. a. Which of your samples inhibited the growth of bacterial colonies the most, and which inhibited the growth of bacterial colonies the least?
[2 marks]
Sample that inhibited growth the most: ........................................................................................ Sample that inhibited growth the least: ........................................................................................ b. Which of these samples would be most effective as an antiseptic?
[1 mark]
........................................................................................................................................................... 2. Calculate the cross-sectional area of your clear areas around colonies. Use
area = πr²
[1 mark]
where r = half of the mean diameter
Give your answer in mm2. ...........................................................................................................................................................
Exam-style questions 1. Four antiseptics were compared for their effectiveness in inhibiting antibacterial growth. The results are shown in Figure 2. Figure 2
a. Identify the independent and dependent variables in this experiment.
[2 marks]
Independent variable: .................................................................................................................. Dependent variable: ....................................................................................................................
AQA GCSE (9–1) Biology Required Practicals Lab Book
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