AQA GCSE Biology B1 Cell Biology: Everything You Need to Know

What's in AQA GCSE Biology B1 Cell Biology?

B1 Cell Biology is the first topic in AQA GCSE Biology and Combined Science. It covers the fundamental building blocks of life — cells — and how they work, divide, and transport substances.

It's a topic that comes up repeatedly throughout the course, so getting it right early pays dividends later.

Key Topics in B1 Cell Biology

1. Cell Structure

You need to know the structures found in animal cells, plant cells, and bacterial cells, and be able to compare them:

• Animal cells: nucleus, cytoplasm, cell membrane, mitochondria, ribosomes
• Plant cells: all of the above plus cell wall, chloroplasts, permanent vacuole
• Bacterial cells: cell wall, cell membrane, cytoplasm, ribosomes, plasmid, chromosomal DNA (no nucleus)

2. Microscopy

You need to understand how to use a light microscope and calculate magnification:

Magnification = image size ÷ actual size

This is also a required practical — you'll need to know how to prepare a slide, focus a microscope, and draw what you see.

3. Cell Division — Mitosis

Mitosis is cell division for growth and repair. Key points:

• Produces two genetically identical daughter cells
• Each daughter cell has the same number of chromosomes as the parent cell
• Stages: prophase, metaphase, anaphase, telophase (Higher Tier)

4. Cell Differentiation and Stem Cells

Most cells differentiate early in development to become specialised. Stem cells retain the ability to differentiate into many cell types — this is why they're important in medicine.

5. Transport in and out of Cells

Three key processes:

• Diffusion — movement of particles from high to low concentration (passive)
• Osmosis — movement of water across a partially permeable membrane from high to low water potential
• Active transport — movement against a concentration gradient, requires energy (ATP)

Osmosis is also a required practical — using potato cylinders in different concentrations of sugar solution.

Higher Tier Only

If you're sitting Higher Tier, you also need to know:

• The stages of mitosis in detail
• How to calculate surface area to volume ratios
• The role of stem cells in treating disease and the ethical issues involved

How to Revise B1 Cell Biology

The best approach is to combine retrieval practice with past paper questions:

1. Use our B1 Cell Biology retrieval questions (Foundation or Higher) to test yourself on the key facts
2. Work through the microscopy and osmosis required practical worksheets
3. Practise magnification calculations using our magnification calculations worksheet
4. Check your answers and make a note of anything you got wrong — those are your priority areas

B1 is one of the most straightforward topics in GCSE Biology — with focused revision, you can master it quickly and free up time for trickier topics later.