Cambridge IGCSE Biology practice
Try the question first, then check the answer and practise the same topic again.
At a glance
MCQ
Type
cambridge_mcq
Style
Topic
Biotechnology
Exam-style question
Which of the following is NOT an enzyme commonly found in biological washing powders?.
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Common mistake
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Flashcard 1 of 6
Question 1 of 5
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Method
1. Cut identical pieces of white cotton fabric stained with egg (protein stain). 2. Prepare three washing solutions: one with biological washing powder, one with non-biological washing powder, and one with water only. 3. Soak each stained fabric piece in the respective solution at 30°C for 30 minutes. 4. Rinse and dry the fabric pieces. 5. Compare the stain removal visually or using a colorimeter.
| Step | Description |
|---|---|
| 1 | Prepare identical stained fabric pieces |
| 2 | Prepare washing solutions |
| 3 | Soak fabric pieces at 30°C for 30 minutes |
| 4 | Rinse and dry fabric |
| 5 | Compare stain removal |
Identify the independent variable in this investigation.
Aim for approximately 1 distinct marking point.
Describe how you would ensure the investigation is fair and reliable.
Aim for approximately 2 distinct marking points.