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Protists (Algae (Aquatic organisms that contain chlorophyll (includes…

- - - - Break down particles using FOOD VACUOLES (membrane-bound chambers with digestive enzymes)
    - - Free-living live in any environment where there is water at some time in the year
        
        eg zooplankton in aquatic ecosystems, organisms in the soil
      - Parasitic have complex life cycles that occur in the cells, tissues, and bloodstream of hosts
        
        eg species that cause serious human diseases
  - - - Often through binary fission (1 protozoan divides into 2 identical individuals
      - Multiple fission results in several identical individuals
    - - Use CONJUGATION, where individuals from opposite mating strains meet and exchange genetic material
  - - - Allow them to survive despite changes eg nutrient deficiency or temperature changes
      - Protozoans leave cysts once favourable conditions return
  - - - Protozoa = descendants of eukaryotes
  - - - Most have flexible cell membranes and thrust out PSEUDOPODIA (large, rounded cytoplasmic extensions that function in movement)
        
        Pseudopodium forms when ENDOPLASM (inner part of cytoplasm) pushes ECTOPLASM (outer layer) forward to form a blunt, armlike extension
        
        Other pseudopodia retract and cytoplasm flows in direction of new pseudopodium (form of movement = AMEBOID MOVEMENT)
        
        Ameboid movement = form of CYTOPLASMIC STREAMING (internal flowing of cell's cytoplasm)
    - - Uses pseudopodia to surround food then part of cell membrane pinches together to surround food in food vacuole (process = endocytosis)
        
        Enzymes from cytoplasm enter vacuole and digest food (undigested food leaves cell through process called exocytosis)
      - Lives on other protists and engulfs them by phagocytosis