Edexcel GCSE Biology required practicals: A complete guide

If you've been Googling "Edexcel GCSE Biology required practicals" and getting a bit confused by the results, there's a reason. Edexcel doesn't call them required practicals. On the Pearson Edexcel GCSE Biology (1BI0) specification they're called core practicals, and there are 8 of them, two fewer than the 10 on AQA. The content overlaps in places, but the terminology, the numbering, and the way the exam is structured all differ.

This guide walks through all 8 Edexcel GCSE Biology core practicals, where each one sits in the specification, how practical skills are assessed across Paper 1 and Paper 2, and how to revise them so you're ready for any practical-skills question in the exam. If you're on the Triple Science route at Higher tier, this is the full list. Combined Science students cover a subset, more on that below.

You won't be asked to physically carry out an experiment in the exam hall. What Edexcel does ask is whether you understand the method, variables, risks, and expected results well enough to answer written questions about any of them.

Edexcel numbers its core practicals against specification points, so instead of "core practical 1" you'll see them listed as 1.6, 1.10, 1.13B, and so on. The "B" suffix on 1.13B and 5.18B signals Biology-only separate-science content.

Four of the eight sit in Topic 1 "Key concepts in biology", which is unusual – it means Topic 1 practical questions can appear on either Paper 1 or Paper 2, because Topic 1 is common to both papers.

For every core practical you should be able to describe the method, state the independent, dependent and control variables, identify the main risks, and explain the expected results. Here's what each one looks like in practice.

You prepare a slide with a specimen (often onion epidermis or cheek cells), add a drop of water and a stain such as iodine, then lower a coverslip to avoid trapping air bubbles. Starting on low magnification, you focus and then switch to higher power. You need to calculate total magnification (eyepiece multiplied by objective) and use the formula real size = image size / magnification. A labelled scientific drawing is also expected – no shading, clear lines, labels with ruled leader lines.

Exam questions often give you a photomicrograph with a scale bar and ask you to work out the actual size of a cell.

Amylase breaks down starch into sugars. You set up amylase and starch at different pH values using buffer solutions, then sample every 30 seconds onto a spotting tile containing iodine. When the iodine stops turning blue-black, the starch has been fully broken down. The time taken is your dependent variable; pH is the independent variable. Control variables include concentration of amylase, volume of solution, and temperature.

Amylase works fastest at its optimum pH (around neutral) and is denatured at extreme pH – the active site changes shape so the substrate no longer fits, and this change is permanent.

You need to know four tests. Benedict's reagent turns from blue to green, yellow, orange or brick red on heating with reducing sugars. Iodine solution turns from brown-orange to blue-black with starch. Biuret reagent turns from blue to purple with proteins. The emulsion test for lipids involves dissolving the food in ethanol, then adding water – a cloudy white emulsion means lipids are present.

Exam questions commonly give you a table of results and ask you to identify which nutrients an unknown food sample contains.

Cylinders of potato cut to equal lengths and masses are placed in sugar solutions of different concentrations. After a set time you blot them dry and weigh them. Independent variable: sugar concentration. Dependent variable: percentage change in mass. Control variables: initial mass, volume of solution, temperature, time submerged.

In dilute solutions the potato gains mass as water enters by osmosis; in concentrated solutions it loses mass. The point where mass doesn't change identifies the solution isotonic to the potato cells.

Agar plates are inoculated with bacteria using a sterile technique, then paper discs soaked in different antiseptics, antibiotics or plant extracts are placed on the surface. After incubation at 25°C (not higher in a school lab, to reduce the risk of growing pathogens), you measure the clear zone of inhibition around each disc. The area of the clear zone is calculated using πr², where r is the radius of the clear zone (half its measured diameter).

Aseptic technique is a favourite exam target: expect questions on why you sterilise the inoculating loop, why the lid is taped rather than sealed, and why you incubate at 25°C.

An aquatic plant such as pondweed (Elodea or Cabomba) is placed in sodium hydrogen carbonate solution under a lamp. You count the bubbles of oxygen released per minute at different distances from the lamp. Moving the lamp closer increases light intensity and increases the rate of photosynthesis, up to the point where another factor becomes limiting.

Light intensity follows an inverse square law – halving the distance quadruples the intensity. Exam questions often give you a graph that plateaus and ask what limiting factor explains the plateau. Counting bubbles is also a classic improvement question: a syringe or gas-collection method is more accurate because bubble sizes vary.

Living organisms such as germinating peas or small invertebrates are placed in a respirometer with soda lime (to absorb carbon dioxide). As the organisms respire, oxygen is used up and the pressure inside drops, moving a coloured liquid along a capillary tube. The distance moved per unit time gives the rate of oxygen uptake.

Exam questions ask you to identify the independent variable (often temperature), explain why a control tube with inactive material is used, and interpret rate curves. Risk-wise you'd flag the use of live organisms and ethics around their handling.

Quadrats are placed randomly (using random-number coordinates) to count or estimate the abundance of a species. Repeated samples are averaged and scaled up to estimate the population in the whole area. A belt transect is a line along which quadrats are placed at regular intervals, showing how a population changes with distance across a habitat (useful for shaded-to-sunlit gradients or shoreline zones).

Exam questions often ask why random sampling reduces bias, how to calculate a mean per quadrat, and how to estimate total population by multiplying the mean by the number of quadrats that would fit in the total area.

There's no separate practical exam. Core practicals are examined through the two written papers, Paper 1 (1BI0/1H), covering Topics 1 to 5 and Paper 2 (1BI0/2H), covering Topic 1 and Topics 6 to 9, each 1 hour 45 minutes and worth 100 marks. Topic 1 is common to both papers, so the four Topic 1 practicals (1.6, 1.10, 1.13B, 1.16) can appear on either.

Assessment objective AO3, "analyse information and ideas to interpret, evaluate, develop and improve experimental procedures", is worth 20% of the overall GCSE. AO1 (knowledge and understanding) is 40%, AO2 (apply knowledge) is 40%. The exact per-paper mark split for AO3 is set out in the Pearson 1BI0 specification; your teacher will have the breakdown.

At least 10% of marks across the qualification come from mathematical skills, which includes practical-based calculations: magnification, percentage change in mass, areas of clear zones, rates per unit time.

If you've switched from AQA or you're revising with mixed-board resources, the main differences are worth flagging. AQA has 10 required practicals, each numbered 1 to 10 and tied to a single topic. Edexcel has 8 core practicals, numbered against specification points, with heavy clustering in Topic 1. Terminology is different ("core practicals" on Edexcel, "required practicals" on AQA), and Edexcel's Topic 1 appearing on both papers is a structural quirk AQA doesn't share. Our AQA GCSE Biology guide maps out the 10 AQA practicals if you're cross-referencing.

Content overlap is high – microscopy, food tests, pH and enzymes, osmosis, antimicrobials, photosynthesis and fieldwork all appear in both specifications. The practical skills themselves transfer across boards; the specific procedures and numbering don't.

When revising with cross-board resources, match by technique not by number. An AQA-numbered microscopy practical maps onto Edexcel 1.6; AQA photosynthesis maps onto Edexcel 6.5. Don't assume "required practical 3" means the same thing on both specs.

No. Edexcel Combined Science (1SC0) covers a reduced Biology list: it drops any content with the "B" suffix (Biology-only separate-science content). That means Combined Science students don't do core practicals 1.13B (food tests) or 5.18B (antimicrobials). The six Combined Science biology practicals are 1.6, 1.10, 1.16, 6.5, 8.11 and 9.5. If you're on Combined, revise those six; if you're on Triple, you need all eight. Our Triple vs Double Science guide explains the differences between the routes if you're unsure which one applies to you.

Reading through the method once isn't enough. Core practical questions check whether you can think like a scientist, going beyond reciting a recipe.

For every practical, flashcard four things: the method (bulleted steps), the variables (independent, dependent, two controls), the main risk and how you'd mitigate it, and the expected result pattern with its scientific explanation. This set of four is what Edexcel questions keep returning to. Write each method out from memory, then compare against your notes – the steps you forget are the ones that would cost marks.

Practise drawing results tables (correct headings, consistent decimal places, independent variable in the left column) and sketching graphs. Then work through past-paper practical-skills questions by topic. The question styles ("suggest an improvement to the method", "identify the anomalous result", "evaluate the student's conclusion") recycle year on year, and the more you see them the faster you'll map a prompt onto a familiar answer structure.

Cognito's Edexcel GCSE Biology course has short video lessons on every core practical, with the method, variables, expected results and exam-style questions all in one place. If you're on Combined Science, the Edexcel Combined Science course covers the six biology core practicals you need. You can also build a revision timetable using the ideas in our how to make a revision timetable guide so core practicals get the time they deserve across the full topic list.