Lecture 13: The Prokaryotic Chromsome

I. Importance

Genetic tool, model for understanding eukaryotic genetics, impact human society

II. General Overview

Precede Eukaryotes

Great diversity

Common features of bacteria

III. The bacterial genome

Circular

IV. Finding Mutations

Genetic screens

Nomenclature

V. Structure and organization of the E. coli chromosome

VI. Transcription

VII. Replication

VIII. Plasmids

Plasmids vary in size ranging from 1kb – 3 Mb.

Plasmids can carry genes that confer resistance to antibiotics and toxic substances.

Plasmids are not needed for reproduction or normal growth, but they can be beneficial.

Plasmids can carry genes from one bacteria to another. Bacteria can thus become resistant to a drug, put the resistance gene in the plasmid, and transfer it to other bacteria. This transfer of plasmid DNA can even occur across species.

IX. Gene Transfer

Conjugation and the F plasmid

Hfr cells

F’ plasmids

X. Complementation testing

Heterogonate, merozygote

XI. Conclusion

Although bacteria are relatively simple organisms that can serve as model organisms for understanding genetic principles, they have complex adaptations to the environment, including sex.

Terms and Concepts to Know: Bacteria nomenclature, transcription, replication, PLASMIDS, gene transfer, transformation, CONJUGATION, transduction, F plasmid, Hfr, F’, Complementation testing, heterogonate, merozygote; Figures: 14.7, 8, 9, 11, 12, 13, 14, 18; Table 2