O Level Biology Practical 2020 Answers __top__ Now

Review: O Level Biology Practical 2020 – An Analysis of Answers and Exam Trends

Exam Session: October/November 2020 (Paper 5090/6 or Equivalent variants) Difficulty Rating: Moderate to Challenging

Breakdown of Paper Sections

Common 2020 Mistakes (That Lost Students Marks)

| Mistake | Correct Approach | | :--- | :--- | | “Benedict’s test went orange” – but didn’t specify which sugar. | “Orange precipitate – reducing sugar present.” | | “Iodine turned black.” | Must be blue-black for starch. | | “Oxygen was produced.” | Always add evidence: “rekindled glowing splint.” | | Drawing too small or shading. | Large, clear outlines; no shading except stippling. | | Forgetting units in magnification. | Always write e.g., ×250 or “250 times.” |

2020 Follow-up Question (Control experiment)

What control would you use to prove the reaction is due to the enzyme? o level biology practical 2020 answers

Model answer: Use boiled potato extract (or water instead of potato). No bubbles → confirms enzyme was denatured.

📊 Part 3: Data Analysis & Graphing

Context: You were likely given a table of results to plot on a graph. Review: O Level Biology Practical 2020 – An

How to Secure the Graph Marks:

• Axis Orientation: The Independent Variable always goes on the x-axis (horizontal), and the Dependent Variable on the y-axis (vertical).
• Scale: The scale must occupy more than 50% of the grid. Do not use odd scales (like counting by 3s or 7s). Stick to 1s, 2s, 5s, or 10s.
• Plotting: Points should be small "x"s or dots with circles. Large dots covering multiple squares lose accuracy marks.
• Line of Best Fit: Do not just "connect the dots." Look for the trend—is it a straight line or a curve? In Biology, curves often plateau (level off), which is a concept frequently tested in 2020 papers regarding limiting factors.

Part 4: Microscope Drawing – The Onion or Leaf Section (All Variants)

Almost every 2020 O Level Biology Practical ended with a low-power plan drawing. 2020 Follow-up Question (Control experiment)

Typical Question

A student added 2 cm³ of hydrogen peroxide to 1 cm³ of potato extract. Effervescence was seen. The glowing splint rekindled. Explain why.

Introduction

The 2020 O Level Biology Practical examination tested candidates on four core skills: (1) Manipulation & measurement, (2) Observation & drawing, (3) Interpretation & analysis, and (4) Planning & evaluation. While specific answer sheets are confidential, the expected answers followed recurring themes: food tests, enzyme activity, osmosis, transpiration, and microscopy.