Lab 2: Intro to Bacteria and Archaea

• Coccus

a type of morphology thats form is a sphere

• Bacillus

a morphology thats form is rod-shaped

• Helical/Spiral

a morphology thats form is an elongated spiral

• Lateral gene transfer

• DNA moves from one organism to another via specialized processes

• is unidirectional with DNA moving from one organism to another.

• involves usually small portions of a genome

• occurs with three mechanisms

  • congugation

  • transformation

  • transduction

transformation

• process whereby DNA found in the environment (e.g., DNA that came from a cell that died and lysed) are moved into an intact cell.

• This DNA can be incorporated into the chromosomes of the recipient cell - either by crossing over (recombination) with the homologous region in the host (and thus replacing a portion of the recipient cell’s chromosome)

• or via direct insertion (and thereby just adding new DNA to the recipient cell’s chromosome).

• The DNA could also stay as a separate replicating entity

conjugation

• looks similar to mating, but it can occur between distantly related cells, and does not result in offspring.

• generally involves the transfer from one cell to another of a small piece of DNA known as a plasmid.

• In conjugation, a tube called a sex pilus forms between two cells.

• A plasmid in the donor cell replicates and one copy passes through the pilus to the recipient cell.

• The plasmid duplicates inside the recipient cell and the pilus breaks.

• Plasmids frequently carry genes for specialized cell functions and may permit the organism to be an effective pathogen, resist antibiotics, or create products useful in specific circumstances.

transduction

• incorporation of new genetic material into a host through the action of viral particles.

• virus particles carry DNA from one host to another.

• Once in a new host, the transferred DNA can be incorporated into recipient cell’s chromosome or replicate as a separate entity

• Because viruses may infect a wide range of hosts, may move genetic material over large evolutionary distances.

• LUCA

• Microbiome

• Distinguish among the three domains of life; what is LUCA? What are the major characteristics of each of the domains?

• What is LGT and why is it problematic for phylogeny reconstruction?

• Be able to describe what symbioses are using examples from lab. Recognize examples from lab including Rhizobium, Anabaena, and the termite hindgut. Be able to explain how each partner benefits.

• What are microbiomes and what approaches are used to study them?

• Be able to name the type of metabolism an organism uses based on its sources of carbon, electrons, and energy.

• Know the basics of compound microscopy; microscope anatomy, function, slide preparation, and size estimation.

• Be able to give two reasons why morphology is problematic for building phylogenies of Bacteria and Archaea