The cell is the structural and functional unit of living organisms. It was discovered by Robert Hooke in 1665.

National 5 Cell structure The functions of cell organelles Cells are microscopic building blocks of unicellular and multicellular living organisms.

The cell nucleus is the site of many important biological functions of the eukaryotic cell. These processes include transcription, replication, splicing and ribosome biogenesis.

Bacteria are amongst the simplest of organisms - they are made of single cells. Their cell structure is simpler than the cells of animals, plants and fungi.