The second component of the examination focused on plant anatomy, water potential gradients, and precision microscopy/visual analysis. Osmosis and Turgor Pressure Investigations
Clear, sharp, continuous single lines (no sketching or shading).
An analytical point often tested: Benedict’s test is semi-quantitative. A brick-red precipitate indicates a high concentration of reducing sugars, whereas a green or yellow color indicates a trace or moderate amount. Biological Drawing and Magnification
Magnification=Size of Image (Drawing)Size of Actual SpecimenMagnification equals the fraction with numerator Size of Image (Drawing) and denominator Size of Actual Specimen end-fraction o level biology practical 2020 answers
The 2020 O Level Biology Practical exams focused on core experimental skills, including nutrient testing, enzyme activity, and specimen observation. Below are the key questions and recommended answers based on the major 2020 paper variants. 1. Food Tests and Enzyme Activity
Explanation : High temperatures denature the proteins embedded in the cell membrane and disrupt the phospholipid bilayer. This makes the cell membrane fully permeable, allowing the vacuolar red pigment (betalain) to leak out rapidly via diffusion.
Requires ethanol. A positive result shows a cloudy white emulsion. C. Enzyme Investigation (Catalase/Amylase) The second component of the examination focused on
┌────────────────────────────────────────────────────────┐ │ BIOLOGICAL DRAWING CHECKLIST │ ├────────────────────────────────────────────────────────┤ │ [ ] Clean, Single Lines (No sketching/feathering) │ │ [ ] No Shading, Stippling, or Artistic Cross-hatching │ │ [ ] Large Size (Occupies >75% of the designated space) │ │ [ ] Straight, Parallel Label Lines (No crossing lines)│ │ [ ] Labels Positioned Outside the Main Body of Drawing│ └────────────────────────────────────────────────────────┘ Magnification Calculations
: Use a gas syringe or a graduated cylinder to measure volume for better accuracy than counting bubbles. Genetic Diagrams
For the 2020 series, both of these papers were published, providing a comprehensive view of the year's intended practical assessment. A brick-red precipitate indicates a high concentration of
If you are looking for specific past paper questions, I can help you find: The The 2020 Oct/Nov Paper 3/4
: When plotting colorimeter readings against concentration, examiners looked for a smoothly inverted curve: a lower colorimeter light-absorption reading directly corresponds to a higher glucose concentration.
Label lines must be drawn with a ruler, touch the intended structure precisely, and must not cross each other. Magnification Formula: