Unit 3: Chapter 23 Flashcards
Protist Characteristics
- Eukaryotic
- Morpholically diverse to adapt to environments
- Typically larger than bacteria and archaea
- Unicellular and multicellular
- Live in freshwater environments
- contribute to nutrient cycling
What are 2 groups of protists?
- Protists which include algae and protozoans
- Fungi
Antony Van Leeuwenhoek
Described first protozoan “animalcule” in 1674
Protozoa
- animal like protist
- all are microscopic unicellular eukaryotes
- chemoheterotroph
- found in soil and water
- free living organisms
- use cilia and flagella to catch prey
Algae
- plant like protist
- unicellular, filamentous, or multicellular
- aquatic environments
- photoautotrophs
- major producers of oxygen and organic materials
What makes up 80% of Earth’s photosynthesis?
Phytoplankton (algae)
Saprophytes
organisms that secure nutrients from dead organic material by releasing degradative enzymes into the environment
usually grow on decomposing organic matter
Osmotrophy
a form of nutrition which absorb soluble products through cytoplasmic membrane
Holozoic nutrition
Solid nutrients acquired by phagocytosis and food vacuole formation
Mixotrophy
Simutaneously use reduced organic molecules and CO2 as carbon sources (use different types of metabolism)
Protist morphology
- plasmalemma (ectoplasm, endoplasm, pellicile)
- Vacuoles (contractile, secretory, phagocytic)
- cilia/ flagella
- mitochondria and chloroplasts
Plasmalemma
Cell membrane of protists
- ectoplasm
- endoplasm
- pellicle
Ectoplasm
impacts rigidity to cell body
Pellicle
Consists of the plasmalemma and a relatively rigid layer just
beneath it
Protective and supportive layer or cuticle
Energy production by aerboic protists through
Mitochondria
Energy production by photosynthetic protists through
Chloroplasts
Trophozoites
Actively growing and replicating protists
Encystement
Formation of dormant cyst
- protect against environmental changes
- site for nuclear reoorganization and cell division
- in parasitic species they are infectious stages between host
Excystement
A return to favorable conditions may stimulate a cyst to form
In parasite protists, excystement occurs following ingestion by a host
Protist reproduction through
Asexual and sexual reproduction
Asexual reproduction by protists
- binary fission
- multiple fission and budding
Sexual reproduction by protists
- includes formation of gametes
- conjugation: form of sexual reproduction by 2 protozoa where two organisms exchange nuclear material
Why does classifying protists and eukaryotes present challenges?
- size and complexity of genes with large genome with noncoding sequences
- lose structures through evolution
- name and groupings are changed as new evidence emerges
Dinoflagellates
- Algae, plant like protists
- 2 flagella, one flagella wrapped around cell
- cause phosphoresence in ocean
- cause neurotoxins
- bloom of red dinoflagellates cause famous red tide
Diatoms
- Algae, plant like protists
- frustule: 2 piece cell wall of silica
- contain chlorophyll and pigments
- important in global carbon cycling (AKA ocean forest)
- produce oil drops that are stored
- interested in using diatoms for biodiesel
What produces about 50% of organic ocean carbon?
marine planktonic diatoms
Chloroplastida
- Algae, plant like protists
- photoautotroph
- cellulose cell walls
Red Algae
- Algae, plant like protists
- grow deeper in ocean than other algae
- source of agar and largest group of seaweeds
Euglenozoa
Primitive eukaryotes
Have features of both algae and protists
debatable on if algae or protists
Trypanosomes
- protozoa, animal like protists
- pathogenic euglenozoa
- parasitic infection via vector
- parasites of animals and plants
- cause chagas disease and african sleeping sickness
Giardia intestinalis
-animal like protist, protozoa
- public health concern with diarrhea from contaminated water
- flagellated and lack mitochondria
- have mitosomes: mitchondria like
- obtain energy without mitochondria through fermentation
Super group amoebozoa
- protozoa, animal like protists
- include pseudopodia which is used for locomotion and feeding
Lobopodia
form of pseudopodia in super group amoebozoa
rounded
Filopodia
form of pseudopodia in super group amoebozoa
long and narrow
Reticulopodia
form of pseudopodia found in super group amoebozoa
netlike mesh
Entamoebida
Under super group amoebozoa, animal like protist protozoa
lack mitochondria and contain mitosomes
cause amoebic dysentery
3rd leading cause of parasitic death worldwide
Naegleria fowleri
Brain eating amoeba
Eumycetozoa
-Under super group: amoebozoa
- Fungi like
- Forms spores
- have acellular and cellular slime molds
Cellular slime molds
Resemble amoeba and ingest phagocytosis
Cells agregate to form stalks and differentiate into spores
Acellular (plasmodial) slime molds
consist of multinucleated mass of protoplasm that engulfs organic debris and bacteria as it moves; move as gigantic amoeba
Phycology
study of algae
Protistology
study of all protists
