Lecture 11 - Protists Flashcards
1
Q
What are the three domains of life
A
- > bacteria
- > archaea
- > eukaryotes
2
Q
What was a mojor driver of eukaryotic evolution
A
Endosymbiosis
3
Q
Primary Endosymbiosis
A
- > gave rise to the first photosynthetic eukaryotes
- > eukaryotes ate prokaryotes and formed a symbiotic relationship
- > this event gave rise to Archaeplastida supergroup (red/green algae, plants)
4
Q
Secondary Endosymbiosis
A
- > eukaryote ate another eukaryote
- > this event gave rise to the members of the Excavata and SAR (Stramenopiles, Alveolates, Rhizarians) supergroups
- > spread photosynthesis throughout the major supergroups from the archaeplastida
5
Q
Evidence for secondary endosymbioses
A
- > some organisms have a nucleomorph (an additional nucleus in the chloroplast)
- > extra membranes around the chloroplast (3-4; extras from vacuole of previous organisms)
6
Q
Archaeplastida
A
- > a monophyletic group containing red algae, green algae, non vascular(mosses) and vascular (ferns and seed plants)
- > dominates fresh water and terrestrial environments
7
Q
Excavates
A
- > mostly are unicellular, heterotrophic (many Euglenozoans are photosynthetic)
- > many are parasites (diplomonads and parabasalids)
8
Q
Explain the three subclasses that make up Excavates
A
Diplomonads
- > reduced mitochondria called mitosomes
Parabasalids
- > reduced mitochondria called hydrogenosomes that release hydrogen
Euglenazoans
- > paraxonemal rods associated with flagella
9
Q
Why do diplomonads and parabasalids have reduced mitochondria
A
- > diplomonads have modified mitochondria that lack a functional ETC and cannot perform cellular respiration; they must get their energy from glycolysis
- > parabasalids are anaerobic and therefore don’t paricipate in oxidative phosphorylation; the hydrogenosomes developed from reduced mitochondria and are where anaerobic metabolism takes place
10
Q
SAR
A
- > very diverse supergroup
- > several unique endosymbiotic events that spread photosynthesis
11
Q
What are the three subclassification of the SAR supergroup
A
Stramenopiles
Alveolates
Rhizaria
12
Q
Stramenopiles
A
- > part of SAR
- > made up of many photosynthetic organisms
- > unicellular, colonial, and multicellular forms
- > common feature is two flagellas, one “smooth” and the other “hairy”(mastigonemes)
13
Q
Alveolates
A
- > sometimes photosynthetic, most not
- > mostly unicellular
- > originally defined by the presence of “alveoli” or sacs under plasma membrane but not all have them
14
Q
Rhizarians
A
- > mostly unicellular amoeboids, some flagellated
- > mostly heterotrophic, except for some cercozoans
- > forams have calcium carbonate shels that commonly fossilize on ocean floor
15
Q
Unikonts
A
- > have a single flagella
- > very diverse supergroup
- > made up of Amoebozoans and Opisthokonts
16
Q
Amoebozoans
A
- > mostly unicellular, some multicellular stages
- > slime molds common in most soils, rotting trees and leaf material
- > amoeba can be free-living or paracites
17
Q
Opisthokonts
A
- > most are not considered protists
- > all heterotrophic
- > rear flagella
- > united by molecular data, few shared morphological traits
