Prokaryotic Cells

1. Prokaryotic Cells

2. What is a Prokaryotic Cell? • Small and simple cells with most being < 1 micron in diameter • It is thought that these were the first type of cells that evolved on Earth • Common example includes bacteria

3. Features of Prokaryotic Cells • Capsule - a polysaccharide layer on outside of cell wall; some bacterial cells have to protect and help with adhesion • cell wall – protects and maintains the shape of the cell; most are composed of a carbohydrate-protein complex called peptidoglycan • plasma membrane – inside the cell wall; it controls the movement of materials in and out of the cell and plays a role in binary fission

5. cytoplasm – the substance that occupies the interior of the cell (where organelles are found); where all cellular process take place • pili – hair-like growths on outside of cell (some bacteria have these); used for attachment esp. to join bacterial cells together so they can swap DNA (conjugation) • flagella – longer than pili; used for movement • ribosomes– site of protein synthesis • nucleoidregion – non-membraned area that contains a single, long, continuous circular thread of DNA

6. plasmids –small, circular DNA molecules that replicate independently from chromosomal DNA; help cell adapt to unusual circumstances

8. Binary Fission • asexual reproduction where DNA is copied, the two daughter chromosomes attach to different regions on plasma membrane, and the cell divides into two genetically identical daughter cells • NO swapping of DNA necessary