Ch. 24 Warm-Up What was Frederick Griffith’s contribution to our understanding of DNA? (Refer back to Ch. 16) How do bacteria replicate?

Lab 6A Warm-Up What are plasmids? What gene(s) are on the plasmid being used in this lab? How can we know if cells have been successfully transformed in this lab?

Bacteria Chapter 24.3

What you need to know: The key ways in which prokaryotes differ from eukaryotes with respect to genome, membrane-bound organelles, size, and reproduction. How horizontal acquisition of genetic information occurs in prokaryotes via transformation, conjugation, and transduction. How these mechanisms, plus mutation, contribute to genetic diversity in prokaryotes.

Genetic Diversity in Prokaryotes Factors: Rapid reproduction (binary fission) Mutations – errors in replication Genetic recombination

Genetic Recombination in Bacteria Transformation: uptake of foreign DNA from surroundings Transduction: viruses transfer genes between prokaryotes Conjugation: DNA transferred from one to another

Transformation Uptake of foreign DNA from surroundings Observed by Griffith (bacteria & mice)

Plasmids Small ring of DNA that carries a few genes Replicates separately from bacterial chromosome Can carry genes for antibiotic resistance (R plasmids) Used frequently in genetic engineering for gene cloning

Using plasmids and bacteria in genetic engineering

Gene Cloning

AP Bio Lab 8 - Transformation

Transduction Viruses (bacteriophages) carry bacterial genes from one host cell to another Recombine DNA of donor and recipient cell

Conjugation One cell donates DNA to another Donors cell extends a sex pilus (“mating bridge”) through which DNA is transferred Requires the presence of a piece of DNA called the F factor to produce the pilus

Conjugation and transfer of F plasmid