O Level Biology Practical 2020 Answers

You would be given a set of data and asked to calculate the mean (average) stem length for the light and dark-grown seedlings.

(Note: This analysis focuses on the widely sat format. If you are sitting a different exam board, the concepts regarding planning and data analysis will still apply.)

This is the hands-on version of the same banana browning experiment described above. However, in the practical test, candidates perform the experiment themselves and record their own observations.

The you want to verify against the marking scheme o level biology practical 2020 answers

The dilute hydrochloric acid prevented browning almost completely—the slice remained creamy yellow throughout the 20-minute observation period. In contrast, the untreated slice gradually turned brown (very pale brown at 10 minutes, pale brown at 20 minutes). The acid likely denatured the enzymes responsible for the browning reaction. The low pH of the HCl (pH 2) created an acidic environment unsuitable for enzyme activity, while the untreated slice remained at pH 6.

Difficulty in counting rapidly rising bubbles accurately, or a drop in water bath temperature during the experiment.

Identifying reducing sugars, starch, proteins, and fats. You would be given a set of data

Practical papers usually require you to observe a specimen (often a flower, fruit, or preserved item) and produce a biological drawing.

Use a gas syringe to measure the exact volume of gas evolved instead of counting bubbles. Use a thermostatically controlled water bath to maintain a constant temperature. Question 2: Food Tests and Biological Drawings

By using the unique 2020 papers as a focused study tool, you are not just practicing Biology—you are learning to think like an examiner and maximising your chances of success. However, in the practical test, candidates perform the

), while a sample that remained blue after two minutes indicated

The official 2020 mark schemes are more than just answer keys; they are a roadmap to exam success. Here’s how to use them effectively:

O Level Biology Practical 2020 Answers: A Comprehensive Guide and Review

Candidates were provided with a solution of an enzyme and its corresponding substrate. They were required to measure the rate of reaction, often by counting gas bubbles produced per minute or tracking a color change using an indicator like iodine solution. Step-by-Step Answer Analysis 1. Constructing the Data Table

Measuring rates (e.g., enzyme activity, reaction rates, seedling growth)