Prokaryotic Genetics


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•  Prokaryotes have one chromosome consisting of a circular DNA molecule

Prokaryotes do not possess a nucleus – instead genetic material is found free in the cytoplasm in a region called the nucleoid

The genetic material of a prokaryote consists of a single chromosome consisting of a circular DNA molecule (genophore)

  • The DNA of prokaryotic cells is naked – meaning it is not associated with proteins for additional packaging

In addition to the genophore, prokaryotic cells may possess additional circular DNA molecules called plasmids

Genetic Material in a Prokaryotic Cell

prokaryote genetics

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•  Some prokaryotes also have plasmids but eukaryotes do not

Plasmids are small, circular DNA molecules that contain only a few genes and are capable of self-replication

  • Plasmids are present in some prokaryotic cells, but are not naturally present in eukaryotic cells

Bacterial cells may exchange plasmids via their sex pili, in a process known as bacterial conjugation

  • This exchange of genetic material allows bacteria to evolve new features within a generation (horizontal gene transfer)

As plasmids can self-replicate and autonomously synthesise proteins, they are ideal vectors for gene manipulation in labs

Overview of Bacterial Conjugation

bacterial conjugation

Micrograph of Bacterial Conjugation via Sex Pili

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