🎯 Microbial Genetics

TARGETS

25. Microorganisms provide essential models that give us fundamental knowledge about life processes.  􏰀 Describe a key study using microbes as model organisms that gave rise to insights about biology
that are applicable across kingdoms and domains (e.g., Griffith’s transformation experiment; Avery, MacLeod, and McCarty’s transformation principle experiment; Hershey-Chase phage experiment; Meselson and Stahl’s semi-conservative replication; Jacob and Monod’s lac operon, etc.).
􏰀 Describe the features of Escherichia coli that have made it a model organism for studying many different life processes.

􏰀 Explain how the rapid growth of microorganisms facilitates evolutionary studies.
􏰀 Use genomic tools to trace a given human gene back to a bacterial ancestor.
􏰀 Describe synthetic biology efforts in bacteria to define the minimal genome necessary for life.

 
16. Although the central dogma is universal in all cells, the processes of replication, transcription, and translation differ in Bacteria, Archaea, and Eukaryotes.  􏰀 State two characteristics of the universal genetic code.
􏰀 State the average size of genes and genomes in a bacterium vs. a human.		 􏰀 Explain how chromosome structure differs in Bacteria, Archaea, and Eukaryotes (e.g., histones and circular/linear chromosomes).
􏰀 Compare and contrast DNA replication in Bacteria, Archaea and Eukaryotes.
􏰀 Explain how the organization of genes in an operon affects transcription in Bacteria, compared to a single gene.
􏰀 Explain the role of mRNA processing in Eukaryotes.
􏰀 List the similarities and differences in transcription initiation and termination between Bacteria, Archaea, and Eukaryotes.
􏰀 List the similarities and differences in translation initiation between Bacteria, Archaea, and Eukaryotes.
􏰀 Present an argument, using the processes of transcription and translation, to explain the evolution of the three branches of cells: Bacteria, Archaea, and Eukaryotes.

 

2. Mutations and horizontal gene transfer, with the immense variety of microenvironments, have selected for a huge diversity of microorganisms.  􏰀 List three mechanisms of horizontal gene transfer in bacteria.
􏰀 State two processes by which mutations can occur.		 􏰀 Describe how mutations and horizontal gene transfer, together with selective pressure, can lead to a rise of antibiotic resistance (or xenobiotic bioremediation or spread of virulence mechanisms).
􏰀 Give an example of a bacterial pathogen that evolved naturally or artificially to become attenuated (e.g., vaccine strains, intracellular pathogens, etc.). Support the example with evidence.
􏰀 Analyze and interpret sequence data to determine if horizontal gene transfer, mutation, or recombination has occurred.
􏰀 Give an example of a trait (e.g., N2 fixation, pathogenicity island, type III secretion, etc.) that is found in diverse bacteria, and provide evidence that explains how that trait came to be found in these diverse bacteria.
4. The traditional concept of species is not readily applicable to microbes due to asexual reproduction and the frequent occurrence of horizontal gene transfer.  􏰀 Describe the general process of sexual reproduction, and how it relates to the definition of
species in eukaryotic organisms.
􏰀 Describe the general process of asexual reproduction/binary fission.		 􏰀 Describe the concept of a species with regard to a core genome and genomic islands.
􏰀 Explain why the traditional definitions of species using reproductive isolation do not apply to Bacteria and Archaea.
􏰀 Discuss one benefit and one problem of this definition of a species: “Bacterial and Archaeal species are often defined when there is more than 70% DNA hybridization among strains.”
17. The regulation of gene expression is influenced by external and internal molecular cues and/or signals  􏰀 State the role of a transcriptional repressor (or activator).
􏰀 Define the role of each of the following: promoter region, RNA polymerase, activator binding
site, repressor binding site/operator, sigma factor.		 􏰀 Describe how bacteria can regulate gene expression at the level of transcription and translation.
􏰀 Explain how gene regulation leads to adaptation.
􏰀 Give examples of how an internal chemical signal can control gene expression.
􏰀 Give examples of how an external chemical signal can control gene expression.
􏰀 Give examples of mechanisms commonly found to regulate the activity of transcription factors,
including types of post-translation modification and the binding of small molecule effectors/ligands.