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Forams Ciliates Euglenozoans Diatoms COMMON ANCESTOR OF ALL LIFE Land plants Animals Amoebas Fungi Red algae Chlamydias Green algae (Mitochondria)* Methanogens Proteobacteria Nanoarchaeotes Thermophiles Domain Eukarya Gram-positive bacteria (Chloroplasts)* Spirochetes Cyanobacteria Domain Bacteria Domain Archaea Review! Who are the Prokaryotes? Who are the Eukaryotes? Who are the single celled Eukaryotes? What do they mean microbial Eukaryotes? Who are the “protists”?

Lynn Margulis

Figure 25.3 Cytoplasm DNA Nucleus Engulfing of aerobic bacterium Engulfing of photo- synthetic bacterium Mitochondrion Mito- chondrion Plastid Plasma membrane Endoplasmic reticulum Nuclear envelope Ancestral prokaryote Ancestral heterotrophic eukaryote Ancestral photosynthetic eukaryote

Figure 25.3 Cytoplasm DNA Nucleus Engulfing of aerobic bacterium Engulfing of photo- synthetic bacterium Mitochondrion Mito- chondrion Plastid Plasma membrane Endoplasmic reticulum Nuclear envelope Ancestral prokaryote Ancestral heterotrophic eukaryote Ancestral photosynthetic eukaryote Proteobacterium Cyanobacterium Archaean cell

Figure Cyanobacteria Proteobacteria Thermophiles Domain Eukarya Domain Bacteria Domain Archaea Fungi Plantae Chloroplasts Mitochondria Methanogens Ancestral cell populations So sometimes whole organisms were engulfed-but genes were also being swapped

1. In the intro to the article they list the kinds of Eukaryotes that have bacterial genes. Who are they? 2. What did we learn about the movement of genes between the mitochondrial genome and the nuclear genome when we read about mitochondrial disease? 3. So when we first started finding Prokaryotic genes in the nuclear genome of Eukaryotes, many argued that their source was……?

g/schaechter/2012/06/how- an-endosymbiont-earns- tenure.html Top of p 869 they talk about Paulinella … Why?

by S. Marvin Friedman Plastids and mitochondria are organelles in eukaryotic cells that originated from bacterial endosymbionts via invasion or enslavement or a synergistic amalgamation, depending on your viewpoint. Since these events occurred more than one billion years ago, it has not been possible to trace the evolutionary steps in the transition from endosymbiont to mature organelle, a process referred to as organellogenesis. Enter the protozoan amoeba, Paulinella chromatophora. …Where does one draw the line between the two? It’s becoming more and more difficult to decide.

4. There is a big section in the middle of this paper “Bacterial genes in eukaryotes: How many are of organellar origin?” What is he arguing here? What is point of this section?

5. Why might Protists be more likely to acquire bacterial genetic material? 6. Why might it be kind of handy for Eukaryotes to retain their ability to acquire “ready to use genes from other sources.”? (top left p 871) 7. At the top of p 871, the authors describe a model or mechanism by which bacteria may end up incorporated into Protists. Describe. What is the problem with this model?

The weak-link model… 8. Why are plants and animals or multicellular organisms in general much less likely to acquire bacterial genes? 9. But what do they mean…“In non-vascular and seedless vascular plants, female gametes are weakly protected in archegonia and exposed to external environments during fertilization.”? (Middle of p871)

10. How about animals, what kinds of animals are more “exposed” and when? 11. Can you decipher Fig. 1??