Flashcards in Lecture 1.1 Deck (14):
What are the three domains?
Bacteria, Archaea, and Eukarya
What defines the domain Bacteria
Majority have cell wall with peptidoglycan
Most lack a membrane-bound nucleus
Ubiquitous and some live in extreme environments
What defines the domain Archaea
Distinguished from Bacteria by unique rRNA gene sequences
Lack peptidoglycan in cell walls
Have unique membrane lipids
Some have unusual metabolic characteristics
Many live in extreme environments
What two classes are in Eukarya
What defines the Eukarya (Protist)
generally larger than Bacteria and Archaea
algae – photosynthetic
protozoa – may be motile, “hunters, grazers”
slime molds – two life cycle stages
water molds – devastating disease in plants
What defines the Eukarya (Fungi)
yeast - unicellular
mold - multicellular
What defines viruses
smallest of all microbes
requires host cell to replicate
cause range of diseases, some cancers
What defines Viroids/Virusoids
infectious agents composed of RNA
What defines Prions
How did we determine the universal phylogenetic tree?
aligned rRNA sequences from diverse organisms are compared and differences counted to derive a value of evolutionary distance
relatedness, but not necessarily time of divergence, is determined this way
What does LUCA (last universal common ancestor) say in regards to how the three domains are related?
Archaea and Eukarya evolved independently of Bacteria
Archaea and Eukarya diverged from common ancestry
What does Endosymbiotic Hypothesis say?
Origin of mitochondria, chloroplasts, and hydrogenosomes come from endosymbiont
Why do we think Cholroplast/mitochondria come from endosymiont?
SSU rRNA genes show bacterial lineage
genome sequences closely related to Rickettsia and Prochloron, respectively