Taxonomy of Eukaryotes Flashcards
Endosymbiosis Theories
- Eukaryotes began as a nucleus-bearing lineage that later acquired mitochondria & chloroplasts by endosymbiosis
- Intracellular association between a H2-producing bacteria gave rise to mitochondria & an H2-consuming archaeal host. Nucleus was later developed
Amitochondriate eukaryotes
Eukaryotes that lack a mitochondrion
Mitosomes
- Reduced form of mitochondrion (no TCA or ETC)
- Involved in the maturation of iron-sulfurclusters
Hydrogenosome
- Present in eukaryotes whose metabolism is strictly fermentative
- carries out the oxidation of pyruvate to H2 , CO2 and acetate
Cysts: Functions
Protect the cells against deleterious environmental conditions
Major clades of Eukaryia
6 major clades:
* Archaeplastida
* Rhizaria
* Chromalveolata
* Excavata
* Amoebozoa
* Opisthokonta
Are eukaryia phylogenetically closer to bacteria or archaea?
Archaea
Archaeplastida: Species
- Red Algae (rhodophytes)
- Green Algae (chlorophytes)
Rhodophytes: Characteristics
- Mostly marine, some freshwater/terrestrial
- Red color is from phycoerythrin
- Mostly multicellular
Chlorophytes: Characteristics
- Mostly freshwater, some marine/terrestrial
- Unicellular (flagellated) or multicellular
- Sexual & asexual reproduction
Excavata: General characteristics
- Unicellular
- Flagellated
- Lacks chloroplasts
- Live in anoxic habitats
Excavata: Species
- Diplomonads
- Parabasalids
- Kinetoplastids
- Euglenids
Diplomonads
- Have 2 nuclei of equal size
- Have mitosomes
- Ex: Giardia (cause giardiasis)
Parabasalids
- Contain a parabasal body
- Have hydrogenosomes
- Ex: Trichomonas (STD in humans)
Euglenoids
Characterised by? Species?
- unicellular flagellated eukaryotes
- Kinetoplastids & Euglenids
Kinetoplastids
- Characterised by presence of kinetoplast
- Ex: Trypanosoma
Trypanosoma brucei (Kinetoplastid)
Disease? Environment? Transmission?
- Causes African sleeping sickness
- Lives and grows in the bloodstream
- Transmitted by the tsetse fly.
Kinetoplasts
A mass of DNA present in
their single, large mitochondrion