Protists Flashcards
Protists structure & protection
Protists are mostly unicellular & microscopic, but some can be multicellular or colonial
Can have cell wall, cell membrane or silica-based shells like diatoms
Pellicles are flexible armor, providing protection without limiting movement.
Motility
Paramecium uses cilia to propel and move itself
Amoeba uses lobe-like pseudopodia to anchor to a solid surface & pull forward
Euglena can use a flagellum to propel itself
Metabolism
Nutrition can be aerobic or anaerobic.
Protists can be photoautotrophs.
Mixotrophs can obtain nutrition through photoautotrophic or heterotrophic routes, depending on the availability of sunlight or organic nutrients.
Heterotrophs consume organic materials from other organisms.
Osmotrophy/ Saprobes absorb nutrients from dead organisms.
Heterotopic routes
Phagotrophic – Engulfing and digesting food particles (e.g., amoebas using phagocytosis).
Parasitism – Feeding off a host, often harming it (e.g., protist p falciparum, which causes malaria).
Asexual Reproduction
Most reproduce asexually, often by binary fission (dividing into two daughter cells).
Binary fission can be transverse or longitudinal, depending on the axis of orientation (e.g., Paramecium).
Multiple fission (e.g., slime molds) produces many daughter cells at once.
Some protists reproduce by budding, where small buds grow and divide.
Habitat
Nearly all protists exist in some type of aquatic environment, several protists are parasites that can infect animals/ plants
Few protists can live on dead organisms or wastes, contributing to their decay
Protists classification
Eukaryote are divided into six super groups
Super groups are protists, animals, plants, and fungi
Each super group is monophyletic - they share a single common ancestor
Excavata
Asymmetrical, single- celled organisms with a feed groove on one side
includes heterotrophic predators, photosynthesis species and parasites
Main subgroups: Diplomonads, Parabasalids and Euglenozoans.
Diplomonads
the intestinal parasite Giardia lamblia.
y have nonfunctional mitochondrial remnants called mitosomes.
Live in anaerobic environments and rely on glycolysis for energy.
Have two identical nuclei and multiple flagella for movement.
Sleeping sickness
T. Brucei causes African sleeping sickness
Changes the thick layer of surface glycoproteins of the human immune system during infectious cycle
Chromalveolates
- Common ancestor that engulfed a photosynthetic red algal cell
- Second endosymbiotic event
-HYPOTHESIS BASED working group that is subject to change
Subdivided into alveolates and stramenopiles
Alveolate’s
Presence of an alveolus: membrane enclosed sac beneath the cell membrane
Dinoflagellates
mixotrophs
cellulose plates used as a protective covering
freshwater & marine
Two flagella: Longitudinal & transverse
Bioluminescence
Production of light through a chemical reaction inside a living organism
Some dinoflagellates do bioluminescence
Paramecium
Has a oral groove to ingest good
Contractile vacuoles that allow the organism to excrete excess water
Cilla to move
Coral Bleaching
loss of relationship from dinoflagellates due to stress from increased temperature, pollutants, or changes in light
Sexual reproduction in paramecium
Created eight daughter cells from two cells
Each cell has a macrononucleus & micronucleus
During reproduction the Marco nucleus dissolve and replace by a micronucleus
Stramenopiles
- Hairy flagellum
- Range in size from single called diatoms to massive & multicellular kelp
DIATOMS
- Unicellular algae protists
-Glassy cell walls composed of silicon dioxide in organic particles
- in freshwater and marine plankton
Diatoms & Carbon removal
Periods of nutrient availability diatom bloom
Excess diatoms die and sink, because they sink they can’t be easily broken down by saprobes
Helps remove carbon dioxide from the air
Biological carbon pump
Process that regulate earths carbon cycle
Golden algae
Unicellular some can form large colonies
Colors results from the extensive use of carotenoids ( photosynthetic pigment)
Found in freshwater & marine environments
Major part of the plankton community
Brown algae
Marine Multicellular organism
Seaweeds
