Investigation of osmosis or transpiration. 2. Detailed Breakdown of Practical Techniques and Answers A. Microscope Work and Biological Drawings

A significant part of the 2020 practical exam involved identifying nutrients or assessing the effect of variables like temperature on enzyme activity.

The drawing should occupy more than half of the space provided on the exam page.

The correct apparatus is a or a pipette (typically a 50 cm³ measuring cylinder). A burette could also be accepted for accurate measurement. Candidates should specify the volume range appropriate for 50 cm³.

One of the most common 2020 practicals involved placing onion epidermal cells or potato strips into salt/sugar solutions of varying concentrations.

Utilizing a thermostatically controlled water bath to maintain a constant temperature.

Are you looking for the 2020 Biology Practical answers? Whether you are a student retaking the exam or a teacher looking for a mark scheme analysis, this guide breaks down the typical challenges found in the 2020 practical session.

Identify sources of experimental error and suggest valid improvements.

Describing the rate of reaction based on the time taken for color change (e.g., shorter time = higher enzyme activity). B. Plant Physiology and Microscopy

The investigation focused on the rate at which banana slices turn brown when exposed to different treatments. The browning occurs because enzymes are released from cut plant tissue, causing reactions between chemicals and oxygen to produce brown pigments.

Using a stopwatch to measure the time for the disappearance of the blue-black color with iodine. D. Osmosis Investigation

: Candidates were asked to provide a line drawing of 5 tubules of a testes and calculate actual diameter using magnification. 2020 Cambridge O Level (5090/31) Practical Key Topics

Good luck with your revision! Remember: Practical Biology is about accuracy and clarity, not just memorization.