topic 7A: protists Flashcards
Domain Eukarya includes 4 kingdoms:
- protists (microorganisms)
- fungi (microorganisms)
- plants (macro-organisms)
- animals (macro-organisms)
what are the two eurkaryotic micro-organisms?
- protists
- fungi
what are the types of protists? give an example of each
- protozoa (e.g. amoebas)
- algae (e.g. seaweeds)
what are the types of fungi? give an example of each
- unicellular fungi: yeasts (e.g. S. cerevisiae - baking yeast)
- multicellular fungi (e.g. mushrooms, molds)
which of the types of protists are pathogenic?
- protozoa is pathogenic
- algae is non-pathogenic
which type of protist can be both unicellular and multicellular?
- fungi - unicellular or multicellular eukaryotic organisms
- protists - mainly unicellular
describe the protist catgories:
(1) protozoa
- do not have cell wall or chlorophyll (no photosynthesis)
- mostly unicellular
- includes several pathogenic species => eukaryotic parasites
- example: amoebas
(2) algae
- non-pathogenic (no need to know)
- have cell wall and chlorophyll
- photosynthetic organisms
- some species are multicellular
- example: seaweed
besides the 4 kingdoms of Domain Eukarya, with new phylogenetic analysis, we also have the division of the:
supergroups
what are the four supergroups of Eukarya?
SOS!!!
(1) Excavates
(2) SAR
(3) Archaeplastids
(4) Unikonts
what supergroup does the plant kingdom belong to?
SOS
Archaeplastids
what supergroup do animals and fungi belong to?
SOS
Unikonts
what are the 3 protist subgroups of the supergroup Excavates?
SOSSSSSS
- diplomonads
- parabasalids
- euglenozoans
what is the supergroup Excavates characterized as?
it is characterized by the presence of a feeding groove in some members
list the subgroups of Excavates and an example of each
SOSSS
(1) diplomonads - Giardia Intestinalis
(2) parabasalids - Trichomonas vaginalis
(3) euglenozoans - Trypanosomes (which includes 2 pathogenic species in its genus)
what are the characteristics of Diplomonads?
flagellated protozoa with modified mitochondria
what is the type of modified mitochondria in Diplomonads?
SOS
mitosomes
since Diplomonads have modified mitochondria, what does that make them?
anaerobic organisms
(these organelles lack functional electron transport chains and hence cannot use oxygen to help extract energy from carbohydrates and other organic molecules)
what is an example of a Diplomonad parasite?
SOS
Giardia intestinalis or Giardia Lamblia
what does Giardia intestinalis cause?
SOS
it is a pathogenic parasite that causes gastroenteritis (food poisoning)
how does the transmission of Giardia intestinalis (or the disease it causes - gastroenteritis) occur?
SOS
food-borne disease
what are the characteristics of Parabasalids?
flagellated protozoa with modified mitochondria
what is the type of modified mitochondria in Parabasalids?
SOS
hydrogenosomes
(because they produce hydrogen gas as a byproduct)
what is an example of a Parabasalid parasite?
SOS
Trichomonas vaginalis
what does Trichomonas vaginalis cause?
SOS
- causes vaginitis in women
- causes urethritis in men
how does the transmission of Trichomonas vaginalis (or the disease it causes) occur?
sexually transmitted disease
what are the morphological characteristics of Euglenozoans?
spiral or crystalline rod inside their flagella
what are the two types of Euglenozoa?
- Kinetoplastids: include pathogenic species (e.g. trypanosomes)
- Euglenids (non-pathogenic = don’t need to know)
what is a characteristic of Kinetoplastids?
have a single mitochondrion
what is an example of pathogenic species in Kinetoplastids?
Trypanosomes
the genus of trypanosomes contains 2 important pathogenic species, what are they?
(1) Trypanosoma Brucei
(2) Trypanosoma Cruzi
what does Trypanosoma Brucei cause?
causes sleeping sickness in humans (African trypanosomiasis)
how is sleeping sickness in humans (African trypanosomiasis) transmitted?
transmitted by the tsetse fly (genus Glossina)
what are the symptoms of sleeping sickness in humans (African trypanosomiasis)
CNS infection => lethargy, coma, death
(therefore, known as sleeping sickness)
what does Trypanosoma Cruzi cause?
causes Chagas’ disease
(American trypanosomiasis)
how is Chagas’ disease (American trypanosomiasis) transmitted?
transmitted by triatomine bugs (genus Triatoma)
what are the symptoms of Chagas’ disease (American trypanosomiasis)?
chronic myocardiopathy
what two Excavates live in anaerobic environments?
diplomonads and parabasalids
what does the supergroup SAR stand for/what groups does it include?
SAR = groups Stramenopiles, Alveolates, Rhizaria
what are the characteristics of Alveolates?
have membrane-bound sacs (alveoli) underneath their plasma membrane
what are the pathogenic species that Alveolates include?
Apicomplexans
what are Apicomplexans?
pathogenic parasites that cause serious human disease
how do Apicomplexans spread?
- they spread through their host as infectious cells called sporozoites
- their apex contains organelles specialized for penetrating host cells and tissues
- require 2 or more different host species for completion of their life cycle
what are the pathogenic species included in Apicomplexans?
(1) Plasmodium malariae
(2) Toxoplasma gondii
what does Plasmodium malariae cause?
malaria
how is malaria transmitted?
by mosquitos
describe the plasmodium life cycle and how it infects our body
infectious cells:
- sporozoites: infect liver cells
- merozoites: infect RBCs (& digest hemoglobin)
explain what natural selection favors in areas with high prevalence of malaria
natural selection favored selective survival of the thalassemia allele carriers (heterozygotes) in areas with high prevalence of malaria
what does Toxoplasma gondii cause?
toxoplasmosis
how is toxoplasmosis transmitted?
(1) oral-fecal route
- by consuming contaminated raw or undercooked meat
- by ingesting anything contaminated with cat or other animal feces
(2) trans-placental
- from mother to fetus
=> can cause abortion, hydrocephalus, mental retardation of the fetus
what are the 2 groups of the Supergroup Unikonts?
(1) Amoebozoans
(2) Opisthokonts
what are the characteristics of Amoebozoans?
amoebas with lobe or tube shaped pseuodopodia
what are the pathogenic species included in Amoebozoans?
Entamoebas
(animal parasites/pathogens)
what do the Opisthokonts include?
Animal, fungi, and 2 protist groups (non-pathogenic)
what are the pathogenic species included in Entamoebas?
(1) Entamoeba histolytica: causes amebic dysentery
(2) Acanthamoeba: contact lenses eye infection (keratitis, encephalitis
a role of protists in ecological communities is pathogenicity; what are two examples of parasitic protists?
- Plasmodium malariae: causes malaria
- Pfiesteria shumwayae: a dinoflagellate that causes fish kills
