Basic Genetic Elements of a Bacterial Cell
Plasmid DNA:
Types of Plasmids:
Chromosomal DNA:
- Extra chromosomal circular DNA molecules
- Contain an origin of replication and genes coding for antibiotic resistance or enzymes to make specific nutrients
- Vary in size and in the number of genes they cary
Types of Plasmids:
- R-plasmids: These are plasmids containing antibiotic resistance genes. These are genes that allow some disease causing bacteria to develop resistance against commonly used antibiotics
- F-plasmids: These are fertility plasmids which contain genes for making F-pili (reproductive part of transmit DNA during bacterial mating). F-plasmids are transmitted through sexual mating
- C-factors: Colicinogenic factors contain genes coding for toxins, important for survival of bacteria
Chromosomal DNA:
- Large and circular
- Contains a single origin of replication and is bound to the plasma membrane; not bound by a protein envelope
- Confined to a region called the nucleoid region
- Replicates once per cell division while attached to the plasma membrane (plasmids replicate independent of bacterial cell division)
Binary Fission
Binary Fission is a method of asexual reproduction by "division in half." In prokaryotes, binary fission does not involve mitosis, but in single celled eukaryotes that undergo binary fission, mitosis is part of the process.