1. Microbial Genetics

2. DNA is the Genetic Material Griffiths Avery et al.

4. DNA: The Genetic Material

6. Central Dogma

8. DNA Replication Semi- conservative Fidelity of information transfer to new strands depends on base-pairing of nucleotides

10. Transcription Synthesis of mRNA strand off of a DNA template mRNA carries the genetic information (message) to the ribosomes Only one strand of DNA is used as a template

11. RNA Three types –mRNA –rRNA –tRNA All three molecules needed for protein synthesis (translation)

12. Transfer RNA (tRNA) “Clover-leaf” shaped molecule Functions to transport amino acids to ribosomes and insert them into proteins One end interacts with aa; other with mRNA

14. Translation

15. The Genetic Code

16. Control of Genetic Expression Operons

17. The Lac Operon

20. Genetic Exchange in Bacteria Transformation Transduction Conjugation

21. Genetic Exchange Bacteria have three different ways in which “new”, donor genetic material can be acquired Once the DNA gets into the cell it may be –Degraded –Incorporated into the genome –Persist independently

22. Transformation Remember Avery et al. Transfer and incorporation of a piece of naked DNA

23. Transduction DNA is carried by a phage Defective phages and lysogeny

24. Conjugation Physical contact (via a sex pilus) between two cells Transfer of a piece of DNA through the pilus Useful in mapping bacterial chromosome Conjugation and bacterial sex F +, F -, and Hfr strains

25. Plasmids Extrachromosomal pieces of DNA Usually carry nonessential, but important traits –Resistance plasmids –Degradative plasmids –Cryptic plasmids

26. Applications of Molecular Genetics Detection and Identification of Microorganisms

27. Molecular Probes If the sequence of an organism is known (or a portion of the sequence), it is possible to design a molecular probe for that sequence. Amplification of a sequence (probe): PCR Direct detection: FISH probes Other molecular methods

29. FISH Probes