CH28 Flashcards
Define
Protists
Diverse group of eukaryotes than span all 4 supergroups: amoebozoa, excavata, plantae, opisthokonta.
Define
Primary endosymbiosis
Formation of a chloroplast (plastid) from an endosymbiotic cyanobacterium. Led to the creation of Archaeplastida (land plants, algae)
Define
Secondary endosymbiosis
Plastic acquisition eevents that followed primary endosymbiosis
Describe
Nucleomorphs
Group of organisms that possess vestigial nuclei: chlorarachnophytes and cryptomonads. They possess double membranes with nuclear pores and densely packed genes
They are evidence for secondary endosymbiosis.
Describe
Excavata
Group of protists, possess excavated feeding groves on one side of cell body. Include diplomonads, parabasalids and euglenozoans
Describe
Diplomonads
Possess no plastids and modified mitochondria called mitosomes (no ETC, anaerobic pathways for energy).
Two nuclei and multiple flagella
Describe
Parabasalids
Possess reduced mitochondria called hydrogenosomes.
They perform anaerobic energy production, which releases H
Describe
Euglenozoans
Defined by the presence of a rod containing a spiral or a crystalline structure inside the flagella. Subdivided into kinetoplastids and euglenids
Describe
Kinetoplastids
Possess large mitochondrion with thousands of DNA organized in interlocking circles called kinetoplasts
Ex: trypanosomes (pathogens)
Describe
Euglenids
Possess pocket at one end of cell from which one or two flagella emerge. They are either mixotrophs or prey engulfers
What are the members of the SAR clade?
Stramenophiles, alveolates and rhizarians
Stramenophiles and alveolates originated billions of years ago
Describe
Stramenophiles
Possess flagellum with fine, hairlike projections and a second, smooth flagellum. Subdivided into diatoms, golden algae and brown algae
Describe
Diatoms
Unicellular algae with a glass-like wall that can withstand pressure
Describe
Golden Algae
- Mixotrophic or photosynthetic
- Color given by colored carotenoids
- Can form protective cysts that can survive for decades
Describe
Brown Algae
- Most complex stramenophiles, they are commonly called seaweeds
- Possess root holdfalst, stemline stipe, leaflike blades near water surface
- Analogous to other plants, algaes
Describe
Alveolates
Possess membrane-bound sacs right (alveoli) under membrane.
Dinoflagellates, apicomplexans and ciliates belong to this group
Describe
Dinoflagellates
Reinforced by cellulose plates, its two flagella are in groves to make the dinoflagellate spin.
A big rise in their number is called a bloom, which causes a phenomenon called “red tide”
Describe
Apicomplexans
They are parasites in their sporozoite stage. Contains complex specialized for penetration
Describe
Ciliates
- Predators who use cilia to move and feed
- 2 nuclei, micro and macro in multiple units
- Micro: exchange of genetic information, led to
- Macro: transcription
Describe
Rhizarians
- Many of them are amoebas, move and feed with pseudopodia, extensions that can budge from anywhere on cell surface
Describe
Forams
Rhizarians, possess porous shells called tests, from which the pseudopodia extend
Describe
Cercozoans
Rhizarians; feed with threadlike pseudopodia. Most are heterotrophs, many are parasites
Which organisms are in Archaeplastida?
Red and green algae as well as land plants.
Red algae’s chlorophyll is masked by phycoerythrin, while green algae are chlorophytes or charophytes
Describe
Unikonts
- They are close to animals, fungi and protists
- Divided into two clades: amoebozoans and opisthokonts
Describe
Amoebozoans
- Lobe/tube shaped pseudopodia
- Counts amongst its ranks mycetozoans (analogous ressemblance to fungi), tubulinids (near hydrated environments) and entamoebas (parasites)
Describe
Opisthokonts
Animals, fungi and protists
