Protists Flashcards
Protists are eukaryotes
Have membrane-bound nuclei and membrane-bound organelles
Protista belong to kingdom Protista
1. Molecular dat (DNA) - organisms not closely related
No longer have kingdom Protista but organisms are still called protists
Endosymbiosis
Serial endosymbiosis
Smaller prokaryotes engulfed by larger prokaryotes - eukaryotes
Plasma membrane enfolded - nuclear membrane + ER
Mitochondria were present in eukaryotes before plastids
Diversity of eukaryotes through endosymbiosis
A lineage of eukaryotes acquired another symbionts = cyanobacterium = primary endosymbiosis
Evolutionary divergence gives rise to red and green algae
Secondary endosymbiosis of red and green algae by other eukaryotes - protests
Diversity of protists
Structure 1. Single celled 2. Colony 3. Multicellular Nutrition 1. Photoautotrophs 2. Heterotrophs (Absorb organic compounds or ingest them) 3. Mixotrophs (both heterotrophs and autotrophs) Reproduction 1. Asexual 2. Sexual 3. Both methods
Domain Eukarya: Excavata
Membrane bound nuclei and organelles
First supergroup Clade excavata
All members have a feeding group on the side of their body (cell)
Diplomonads & parabasalids
1. Lack plastids: heterotrophs
2. Have modified mitochondria
Dplomonads
1. Mitochondria - mitosomes
2. Use glycolysis only to produce ATP
Parabasalids
1. Small mitochondria - Hydrogenosomes
2. Use anaerobic respiration and use hydrogen gas as a byproduct
Euglenozoans
1. All have a spiral or crystalline rod in their flagella
2. Divided into 2 groups: kinetoplastids & euglenids
Kinetoplastids: organized mass of DNA in their mitochondria
Euglenids: mixotrophs
Giardia: parasite
Parabasalids: trichomonas vaginalis - parasite that eats lining of vagina
Trypanosoma
Trypanosoma causes sleeping sickness - infected if bitten by tsetse fly which is the vector that carries trypanosoma Evades immune system by using a form of defense called bait and switch Has proteins (single type) on the surface of the cell - new generation of trypanosoma is produced that has a new protein on the cell surface Body can't recognize trypanosoma as foreign and promote an attack because it keeps changing
Chromalveolates
Formed through secondary endosymbiosis of red algae
Has 2 Clades
Alveolates: membrane-bound sacs (alveoli) under the plasma membrane
1. Regulates water and ion concentrations
2. Maintains water balance
3. Stabilize cell surface
Stramenophiles
1. Marine algae
2. Important photosynthetic organisms on earth
3. Produce a large amount of organic matter (food)
4. Use flagella for movement
Dinoflagellates
Free-swimming, unicellular, have 2 flagella
Dinoflagellate blooms - when population increases dramatically - red tides
1. Harmful effect on sea life & consumers of sea life
2. Toxins that are produced by the red tides works its way on the food chain very quickly
3. Can cause gastrointestinal problems, permanent neurological problems, and death
Ceratium dinoflagellates
1. Large protrusions are used for protection from predators
Noctiluca
1. Bioluminescent
2. Flagella to capture prey
Apicomolexans
All apicomolexans are parasites
Plasmodium: malaria
1. Requires 2 hosts: mosquito & human
2. Has a protein coat that it changes to evade immune system of host
3. Lives in the red blood cells - makes it difficult for our immune system to attack
(For slide below!)
Ciliates
Paramecium
1. 2 nuclei
Macronucleus: controls every day cell functions: waste removal, feeding, maintaining water balance
Micronucleus: swapped during conjugation of opposite mating types - increase genetic diversity in population
Diatoms
Diatoms: unicellular algae
1. Produce overlapping cell walls that are made of silica
2. Photosynthesize and incorporate carbon dioxide into their bodies - when they die, carbon dioxide is held within cell walls
3. Trap a lot of carbon dioxide and decrease global warming
Important commercially
1. Fine abrasive silver polish & tooth paste
2. Insulation
3. Filters
Golden algae
Most are unicellular
Some are colonial
Color due to yellow & brown pigments called carotenoids
Have 2 flagella near one end of the cell
Brown algae
Largest and most complex of all algae
1. Have cellulose cell walls & gel for,ing polysaccharide (algin)
Cushion against waves
Prevents desiccation
2. Some brown algae may have gas-filled air sacs (air bladders) which allow blades of the algae to float at the surface of the water for photosynthesis
Laminaria: food source
1. Used to thicken ice cream, pudding, salad dressings
2. Used to make Japanese soup kombu
Oomycetes
Top left: white rust Bottom left: downy mildew Top right: water mold Water mold: decomposer (breaks down organic matter) White rust & downy mildew: parasites Oomycetes: originally classified with the fungi 1. Bodies are composed of hyphae 2. Have cell walls made of cellulose 3. Molecular data - not related at all Cell walls of fungi made of chitin Potato blight
Radiolarians
Thread-like pseudopods used for locomotion and in feeding
Radiolarians
1.Like diatoms, are unicellular
2. have skeleton made of silica
3. Die - skeletal shells - sink to bottom of ocean - form a layer of ooze 10 cm thick
