1-2: A Diverse World of Microbes Flashcards
What are the three distinct domains of life
Bacteria, Archaea, Eukaryotic microbes
What relates bacteria and arachaea
they are prokaryotes
What are viruses, how do they differ from microbes
Genetic elements (DNA, RNA) that can multiple within a cell
Fundamentally different from microbes
Parasites, NOT CELLS
No metabolism, ribosome
What is LUCA
Last universal common ancestor (between P,A,E)
When did bacteria separate from E and A
over 3.5 bya
Features of LUCA?
DNA replication, transcription, translation
Cell division
ATP as energy intermediate
Lipid bilayer membrane
Anaerobic metabolism (no O2)
What are chemotrophs vs phototrophs
Chemo: energy from released bond E from chemical compounds
Photo: absorb light, transform to chemical energy
What is anoxic
When the atmosphere was devoid of oxygen (first 2 billion years)
What changed to lead to the rise of atmospheric O2
Rise of photosynthetic bacteria (cyanobacteria) that produce oxygen as waste product
What does the ozone layer do
Protects against UV (damages DNA), makes planet habitable
What makes O2 special, what kind of organism did it give rise to
Great electron acceptor
Rise to aerobic organisms (efficient E production)
What is the endosymbiotic theory
Evolution of eukarya was archaea-like ancestor engulfing an aerobic respiring bacterium (Alphaproteobacteria) which becomes an organelle = endosymbiont, genes transfer
What is an endosymbiont
Organism living within another organism
How did plants emerge
Engulfed photosynthetic bacterium (cyano) = chloroplast
What are the two versions of the endosymbiotic theory
Serial endosymbiosis hypothesis (engulfed post-nucleus formation)
Symbiogenesis hypothesis (engulfed prior to nucleus/E&A split)
