Prokaryotes are single-celled organisms. Prokaryotic cells are much smaller than eukaryotic cells and they lack membrane-bound organelles, with a diameter of less than 2μm. They have the following organelles:
- Cytoplasm
- Ribosomes
- Cell-surface membrane
- Cell wall (made from murein)
- Plasmids - loops of DNA that are not part of the circular DNA, but they are not present in all prokaryotic cells
- Flagellum (plural is flagella) - a long, hair-like structure, used to help the prokaryote move, not present in all cells
- Circular DNA - a coiled strand of DNA which is not associated with histones
- Capsule - composed of slime, helps the bacteria when being attacked by the immune system
How do prokaryotes replicate?
Prokaryotic cells replicate through binary fission - producing two daughter cells.
- The circular DNA and plasmids are replicated
- The cell increases in size and the DNA moves to opposite sides of the cell
- The cytoplasm starts to divide and the new cell wall starts to form
- The cytoplasm divides, two daughter cells are produced with one copy of the circular DNA and a variable number of plasmids