1. Bacteria, Archaea, & Protista
Chapter 24

2. What you need to know! Different Domains of unicellar organisms
How chloroplasts and mitochondria evolved through endosymbiosis
Protista is no longer considered an independent kingdom. They are part of the Eukaryotes domain and are very diverse.
How Chloroplasts and mitochondria evolved through endosymbiosis

3. Domains
Bacteria
Archaea
Eukarya

4. Characteristics of Prokaryotes (both domains)
No membrane bound organelles
Smaller ribosomes
Haploid (no meiosis)
Can have plasmids (horizontal gene transfer)
Can have flagella (made of flagellin not tubulin)
Evolved all metabolic pathways on earth
Photoautotroph, chemoautotroph, photoheterotroph, chemoheterotroph
Classified based on: metabolism then shape then staining
Cell walls (different molecular make-up)
Reproduce via binary fission

5. Eubacteria Characteristics
Identified by shape: cocci (sphere), bacilli (rod), spirilla (spirals)
Distinguished by staining method
Gram positive = outer cell wall
Gram negative = inter cell wall (between 2 membranes)
Cyanobacteria (formerly blue/green algae): photosynthetic, some fix nitrogen
Chemosynthetic bacteria: autotrophs, some fix nitrogen
Nitrogen Fixing Bacteria: heterotrophs, mutualistic with plants, live in modules
Endospores: DNA packed into cell wall for long term hybernation/survival

6. Types of Archaeabacteria
Methanogens: anaerobic, chemoheterotrophic (obligate anaerobes), produce methane; found in: deep-sea hydrothermal vents, mud, swamps, guts of cows, and termites
Extremophiles:
Extreme Halophiles: aerobic, heterotrophic, or anaerobic, photosynthetic (with pigments), live in high salinity (Salt Lake, Dead Sea)
Extreme Thermophiles: chemosynthesis, autotrophs, live in high heat (150 – 180 degrees F)

7. Horizontal Gene Transfer
A process in which genes are transferred from one genome to another by methods other than reproduction:
Transformation: uptake of foreign DNA
Viral infection
Transduction: viruses (accidentally) transfer non viral genes from their maker to their host
Conjugation: Exchange of transposable elements (plasmids) from source to target
Fusions of organisms endosymbiotic hypothesis

8. Protista ≠ Kingdom

9. Characteristics Protists are eukaryotes
Can be unicellular, colonial or multicellular
Predecessor to other eukaryotes: plants, fungi, and animals.
Eukaryotic fossils date back 1.8 billion years
Some of the most complex cell structures found
Special organelles: contractile organelle (primitive excretion, H20 balance), eye spots (primitive sight), anal pores (primitive waste excretion)

10. Endosymbiotic Hypothesis

11. Metabolism
Protists are the most nutritionally diverse of all eukaryotes:
Most protists are aerobic, with mitochondria for cellular respiration.
Some protists are photoautotrophs with chloroplasts.
Still others are heterotrophs that absorb organic molecules or ingest larger food particles.
A few are mixotrophs (heteroautotrophs), combining photosynthesis and heterotrophic nutrition

12. Specifics Absorptive, protists (fungus-like)
Protozoa - ingestive, animal-like protists
Algae - photosynthetic, plant-like protists.
Features:
Flagella: Protists have a flagella or cilia during some time in their life cycles.
The eukaryotic flagella are extensions of the cytoplasm with a support of a microtubule system (made from tubullin)
Cilia are shorter and more numerous than flagella.

13. Reproduction protists can reproduce asexually or sexually
Many protists form resistant cells (cysts) that can survive harsh conditions.
Protists are the first group to show “alternation of generation”:
Most protists are haploid organisms (n), called gametophytes
Gametophytes produce gametes
Gametes fuse to form a zygote
The Zygote develops into a sporophyte (not the main organisms)
The Sporophyte produces haploid spores that germinate into gametophytes

14. Habitat Protists are found almost anywhere there is water:
Oceans, ponds, and lakes, but also damp soil, leaf litter, and other moist terrestrial habitats.
Protists are also important parts of the plankton, communities of organisms that drift passively or swim weakly in the water.
Phytoplankton (including planktonic eukaryotic algae and prokaryotic cyanobacteria) are the bases of most marine and freshwater food chains.

15. Lifestyle
Many protists are symbiots that inhabit the body fluids, tissues, or cells of hosts.
These symbiotic relationships span the continuum from mutualism to parasitism (malaria, giardia)

16. Euglena Part of phytoplankton mixotrophic
Base of marine and fresh water food webs

17. Amoebas Pseudopods, extensions of the cytoplasm
Capturing prey, locomotion
Heterotrophic

18. Radiolarians
Skeleton pseudopods to increase surface area

19. Foraminiferans
Beautifully shaped calcium carbonate or silica shelled protists

20. Paramecium Coordinated movement through ciliates
Complex organelles: contractile vacuole for osmoregulation (pumping out water)

21. Malaria (protozoan)
transmitted by infected mosquito

22. Phylum Crysophyta/Diatoms
Abundant in plankton and sediments
Have silica shells
Top and bottom shells fit together like boxes

23. Well Known Members Infamous: Giardia Trypanosomes Malaria Cute
Paramecium
Amoeba
Mistaken as other organisms
Brown, green, and red algae
Giant Kelp

24. Critical Vocabulary Obligate aerobes: need oxygen environment to live
Obligate anaerobes: need an oxygen free environment to live (absolutely no oxygen)
Facultative anaerobes: can survive w/ or w/out oxygen