Features common to all living cellsSpec 3.1
In short
All living organisms are made of cells. Every cell has a cell surface membrane, cytoplasm, genetic material in the form of DNA, ribosomes for protein synthesis, and metabolic reactions catalysed by enzymes. Eukaryotic cells keep their DNA in a nucleus and have membrane-bound organelles, whereas prokaryotic cells have neither.
The cell theory says that all living organisms are made of cells and that the cell is the basic unit of life. Cells vary hugely in size and shape, but they share some common features.
- a cell surface membrane that controls what enters and leaves the cell
- cytoplasm, the gel-like fluid in which metabolic reactions take place
- genetic material, which is DNA, carrying the instructions for making proteins
- ribosomes, the sites of protein synthesis (translation)
- metabolic reactions, which are controlled by enzymes and use ATP as the energy currency
| Feature | Eukaryotic cell | Prokaryotic cell |
|---|---|---|
| DNA | Linear, in a nucleus with a nuclear envelope | Circular, free in the cytoplasm (not in a nucleus) |
| Membrane-bound organelles | Present (for example mitochondria, Golgi apparatus) | Absent |
| Ribosomes | Larger (80S) | Smaller (70S) |
| Examples | Animal, plant and fungal cells | Bacteria |
A common-features question wants the feature and what it does. Write 'ribosomes, which make proteins', not just 'ribosomes'.
Written and checked against the Edexcel International AS Level Biology (XBI11) specification · Updated October 2026