Fiducia TogetherCell
The basic unit of living things, and the difference between the two types.
Please note: This page explains a word or a process in education. It is general information about the system, the law and the guidance in England — not advice about your child, your school or your exam. If a decision is going against you, get advice from one of the free services we link to before you agree to anything or miss a deadline. If you are revising, check your own exam board's specification: boards word things differently and yours is the one that marks you.
What it is
All living organisms are made of cells. Eukaryotic cells — animal, plant, fungal — have a nucleus and membrane-bound organelles. Prokaryotic cells, such as bacteria, do not: their genetic material is a single loop of DNA plus plasmids.
Where it applies
GCSE biology and combined science.
How it works
Structures worth knowing and what each does: nucleus (holds DNA), mitochondria (aerobic respiration), ribosomes (protein synthesis), cell membrane (controls what enters and leaves), and in plants a cell wall, chloroplasts and a permanent vacuole.
Specialised cells — sperm, nerve, root hair, red blood — are adapted in ways questions ask you to link to function.
How to use it in your work
For any specialised cell, the answer is always adaptation → how it helps the function. "A root hair cell has a large surface area, so more water is absorbed."
Learn the order of magnitude: a bacterium is around 1 micrometre, an animal cell around 10 to 100. Questions use standard form here.
Where to get help
Your teacher, your board's specification for the depth required at your tier, and Bitesize for the diagrams. The subject song runs the topics in order.
Revise this with a song
These are ours. We write revision songs because a lot of people remember a tune when they cannot remember a page, and because revising out loud in the kitchen beats staring at a highlighter.
- The Biology Song The GCSE biology specification, set to music.
Where to read more
Last reviewed 2026-08-28 by Fiducia Together · Next review due 2027-08-28
Please note: This page explains a word or a process in education. It is general information about the system, the law and the guidance in England — not advice about your child, your school or your exam. If a decision is going against you, get advice from one of the free services we link to before you agree to anything or miss a deadline. If you are revising, check your own exam board's specification: boards word things differently and yours is the one that marks you.