WJEC A2 Biology Unit 5 Experimental Task — Worked Answers
The Unit 5 Experimental Task (paper 1400U50-1A) is the practical examination where candidates carry out a set practical, record their own results, draw a graph and answer 20 marks of questions on consistency, sources of inaccuracy and how the method could be improved. Past-paper answers for it are almost impossible to find. This pack gives you full worked answers to every Experimental Task from 2017 to 2024 — model results, properly drawn WJEC-style graphs, model answers to every part, and examiner tips on exactly what the mark scheme rewards and rejects.
What’s inside
A 33-page PDF booklet covering all six available Experimental Tasks. For every year you get two complete worked datasets — a clean set of model results, and a second worked example that deliberately shows inconsistent data so you can see how to discuss anomalies and long range bars — each with everything the mark scheme is looking for.
WJEC-style results tables
Laid out exactly as WJEC expects — units in the headings only, a single main heading over the repeats and mean, no Range column.
Properly drawn graphs
Ruler-straight lines on a real WJEC grid, points as crosses, vertical range bars — drawn the way the plotting marks demand.
Model answers to every part
Consistency, sources of inaccuracy with matching improvements, controls and modifications — phrased the way the mark scheme expects.
Examiner tips
Each part flags the points candidates lose marks on — including the answers the mark scheme explicitly rejects.
A “spot the anomaly” dataset
The second dataset each year shows scattered, inconsistent results so you learn to criticise data with evidence, not vague phrases.
Mark-scheme summary
A clear part-by-part breakdown of where the 20 marks come from, so you can mark your own attempt.
The six tasks covered
Click any year to see the practical it covers and the skills it tests. Every one is answered in full in the pack.
2017Action of phosphatase on phenolphthalein phosphate20 marks
Phosphatase from a mung-bean extract releases phenolphthalein from its phosphate; the concentration is read off a colour chart at one-minute intervals. The pack works through the results table, the graph, the consistency answer, two sources of inaccuracy with improvements, and the modification to investigate the effect of pH (with the alternative temperature route the mark scheme also credits).
2018Inhibition of catalase by copper sulfate20 marks
Yeast-soaked discs in hydrogen peroxide, with and without copper sulfate, to test whether CuSO₄ is a non-competitive inhibitor. The pack covers the two-condition results table, the labelled graph, the inhibition-type conclusion (including the fully creditable “cannot tell” route), three sources of inaccuracy, and reliability of the means.
2019Osmosis in potato tissue in seawater20 marks
Potato pieces in seawater, with the percentage change in mass plotted over 30 minutes. The pack covers why percentage change is used, what the range bars tell you, the predicted plateau, the effect of inconsistent drying, and why boiled potato is not a valid control.
2022Amylase activity during barley germination20 marks
Extracts from grains germinated for different numbers of days, timed against iodine until the colour stops changing. The pack covers the conclusion (with how to handle inconsistent data), why the same mass of seeds is used, why the end-point is subjective, the ±10 s resolution, and why amylase activity falls once leaves form.
2023Oxygen uptake in germinating seeds20 marks
A syringe respirometer with germinating mung beans and sodium hydroxide. The pack covers the distance-and-volume table, the straight-line graph through the origin, why the marker fluid moves, the purpose of replacing the air, the boiled-bean control, and why a set volume of beans beats a set number.
2024Substrate concentration and catalase20 marks
Potato-paste discs in hydrogen peroxide of increasing concentration, timed as they fall and rise. The pack covers the trend-and-consistency answer, the boiled-potato control, the pH-buffer improvement (with the alternative water-bath route), and the link to acatalasaemia.
Frequently asked questions
Is this the official WJEC mark scheme?
No. These are original worked answers written by a Chartered Biologist and former WJEC examiner, designed to show you what a full-mark response looks like for each part. Exam questions are paraphrased, not reproduced; for the official papers and mark schemes, use the WJEC website.
Are the student results real?
The two datasets per year are simulated for teaching — one clean, one deliberately inconsistent — so that the answers can demonstrate exactly what the mark scheme rewards, including how to discuss anomalies and range bars.
What format is it and how do I get it?
It’s a single 33-page PDF, delivered instantly after checkout by secure download link and email. You can pay by card, Apple Pay or Google Pay. It’s for personal study use.
Will it help if my exam board isn’t WJEC?
The graph, results-table and evaluation skills are useful for any practical-skills paper, but the specific tasks, mark schemes and wording are WJEC A2 Unit 5. If you sit Eduqas or another board, your own board’s practicals will differ.
Get the worked-answers pack
Every WJEC A2 Biology Unit 5 Experimental Task from 2017 to 2024 — model results, WJEC-style graphs, model answers to every part and examiner tips — in one downloadable PDF.