Chapter 28 Protists Flashcards
Protists are classified into _________
Supergroups
Describe protists
Eukaryotes
Most unicellular, some colonial, some multicellular
Polyphyletic group
More structural and functional diversity than any other group of eukaryotes
Single celled protists can be very complex
What are the different modes of nutrition in protists?
- heterotrophs (absorb organic molecules and ingest larger food particles)
- photoautotrophs (contain chloroplast, algae and euglena)
- mixotrophs (combine photosynthesis and heterotrophic nutrition)
How do you protists reproduce?
Some reproduce asexually only
- binary fission
- schizogony
Some have sexual reproduction
- sporic life cycle
- gametic life cycle
- conjugation
Schizogony
Form of asexual reproduction in protists, Multiple mitosis (makes daughter cells called meroxoties)
The exchange of genetic material between the same species, forms a temporary union, when they separate they are genetically different from the original organism
Micronuclei are exchanged
Form of sexual reproduction
Conjugation
What are the four supergroups of eukaryotes?
Excavata
SAR
Archaeplastida
Unikonta
The plastid-bearing lineage of protists evolved into….
Red and green algae
-the DNA of plastid genes in red algae and green algae closely resemble the DNA of cyanobacteria
On several occasions during eukaryotic evolution, red and green algae underwent ___________, in which they were ingested by a heterotrophic eukaryote
Secondary Endosymbiosis
The super group is characterized by its cytoskeleton
- some members have a feeding groove
- modified mitochondria
- unique flagella
Excavata
What does the supergroup excavata include?
- diplomonads
- parabasalids
- euglenozoans
Part of the supergroup excavata, Lack plastids, have modified mitochondria, and most live in anaerobic environments
- two equal sized nuclei
- mitosomes- reduces mitochondria and no ETC
- multiple flagella
- derive energy from anaerobic biochemical pathways
- often parasites
Diplomonads
Part of the supergroup excavata
Causes parasite giardia (uses adhesion disks that causes nutrient malabsorption)
Also includes trichonympha that inhabits the guts of termites
Diplomonads
- Protozoan-flagellated
- fecal-oral route
Cysts (dormant) release trophozoites (metabolically active form) —> sm intestine —> attaches to wall (adhesion discs) —> inflammation, diarrhea, blacks abs of nutrients
Giardia intestinalis
Part of the supergroup excavata
Hydrogenosomes (mitochondria)
- reduced Mitochondria
- generate some energy anaerobically
Trichomonas vaginalis
Parabasalids
Name of the mitochondria in parabasalids
Releases hydrogen metabolically
Hydrogenosomes
STD, causes vaginitis, strong odor, itchy, discharge, strawberry appearance on cervix, dysuria
Trichomoniasis
part of the supergroup excavata
- predatory heterotrophs
- photosynthetic autotrophs
- parasites
- **Spiral or Crystalline rod of unknown function inside their flagella
Clade- kinetopladtids and euglenids
Euglenozoans
Supergroup excavata
- **Single huge mitochondrion called kinetoplast
- Some free-living consumers of prokaryotes
- parasites (trypanosoma) include sleeping sickness and Chagas’ disease (hard to treat, use bait-and-switch defense)
Euglenozoans- kinetoplastids
Excavata, euglenozoans, kinetoplastids
Bait-and-switch defense
- invade immune system responses by switching surface proteins
- A cell produces millions of copies of a single protein
- The new generation produces millions of copies of a different protein
- these frequent changes prevent the host from developing immunity
Trypanosomes
Parasitic disease of the nervous system that’s transmitted by the tsetse fly
Fatal if untreated do to cells being robbed of glucose
African trypanosomiasis
African sleeping sickness
Parasite caused by reduviid bug “kissing bug”
Acute- Romania’s sign
Chronic-mega esophagus, megacolon, and congestive heart failure
Seen in Mexico, central and South America
American trypanosomiasis:
Chaga’s disease
Supergroup excavata
Flagella that emerge from a pocket at one end of the cell
Has chloroplasts and an eyespot ti detect light
Mixotrophic
Euglenozoans- Euglenids
This super group includes
- stramenopiles
- Alveolates
- Rhizarians
The SAR clade
SAR supergroup
- phototrophs
- most have a “hairy” flagellum paired with a “smooth” flagellum
- they include diatoms, golden algae,brown algae
Stramenopiles