Investigating factors affecting catalase or amylase activity.
This task required observing 15 seedlings grown in light and 15 grown in the dark. Stem Length
) for points and a smooth line of best fit or ruled straight lines as instructed. . Always show working and include the " Accuracy
To prepare effectively, you need direct access to the past papers and their official answers. Here are the most reliable places to find them:
The core goal of the practical paper is to test your skills in a hands-on environment. The syllabus outlines three key skill areas you need to master:
Factors that must be kept constant to ensure a fair test (e.g., the volume and concentration of starch, the volume and concentration of amylase, and the pH of the solution).
Marking notes: show workings for rate calculations, label axes with units, describe trends qualitatively and link to biological explanation.
“Make a large, labelled drawing of the region indicated.”
If you:
Procedure : Add equal volumes of Benedict's solution and the sample into a test tube. Heat in a boiling water bath for 3–5 minutes.
: Record values to a sensible level of precision and always include units in table headers rather than within the data cells themselves.
| Slice | Initial Colour | 5 min | 10 min | 20 min | pH | |-------|----------------|-------|--------|--------|-----| | A (HCl) | Creamy yellow | Creamy yellow | Creamy yellow | Creamy yellow | 2–3 | | B (Cut up) | Creamy yellow | Very pale brown | Pale brown | Brown | ~6 | | C (Untreated) | Creamy yellow | Creamy yellow | Very pale brown | Pale brown | ~6 |
Test unknown solutions (labeled S1, S2, etc.) for the presence of biological molecules. Expected Answers/Observations:
The primarily focused on food tests, enzyme activity, and biological drawings. For the Cambridge O Level (5090) variant, the exam centered on the effect of temperature on beetroot pigment release and photosynthesis in variegated leaves. 1. Singapore O Level (Syllabus 6093/03) - Main Experiments
Use a sharp pencil for clear, clean lines; ensure the drawing is larger than the original specimen and accurately reflects details like fruit segments or tissue boundaries. Magnification Formula: Comparing Flowers: A common task was comparing wind-pollinated flowers (e.g., ) with insect-pollinated ones (e.g.,