topic 7A: protists

Question 1

Domain Eukarya includes 4 kingdoms:

Answer 1

• protists (microorganisms)
• fungi (microorganisms)
• plants (macro-organisms)
• animals (macro-organisms)

Question 2

what are the two eurkaryotic micro-organisms?

Answer 2

• protists
• fungi

Question 3

what are the types of protists? give an example of each

Answer 3

• protozoa (e.g. amoebas)
• algae (e.g. seaweeds)

Question 4

what are the types of fungi? give an example of each

Answer 4

• unicellular fungi: yeasts (e.g. S. cerevisiae - baking yeast)
• multicellular fungi (e.g. mushrooms, molds)

Question 5

which of the types of protists are pathogenic?

Answer 5

• protozoa is pathogenic
• algae is non-pathogenic

Question 6

which type of protist can be both unicellular and multicellular?

Answer 6

• fungi - unicellular or multicellular eukaryotic organisms
• protists - mainly unicellular

Question 7

describe the protist catgories:

Answer 7

(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

Question 8

besides the 4 kingdoms of Domain Eukarya, with new phylogenetic analysis, we also have the division of the:

Answer 8

supergroups

Question 9

what are the four supergroups of Eukarya?

SOS!!!

Answer 9

(1) Excavates
(2) SAR
(3) Archaeplastids
(4) Unikonts

Question 10

what supergroup does the plant kingdom belong to?

SOS

Answer 10

Archaeplastids

Question 11

what supergroup do animals and fungi belong to?

SOS

Answer 11

Unikonts

Question 12

what are the 3 protist subgroups of the supergroup Excavates?

SOSSSSSS

Answer 12

• diplomonads
• parabasalids
• euglenozoans

Question 13

what is the supergroup Excavates characterized as?

Answer 13

it is characterized by the presence of a feeding groove in some members

Question 14

list the subgroups of Excavates and an example of each

SOSSS

Answer 14

(1) diplomonads - Giardia Intestinalis
(2) parabasalids - Trichomonas vaginalis
(3) euglenozoans - Trypanosomes (which includes 2 pathogenic species in its genus)

Question 15

what are the characteristics of Diplomonads?

Answer 15

flagellated protozoa with modified mitochondria

Question 16

what is the type of modified mitochondria in Diplomonads?

SOS

Answer 16

mitosomes

Question 17

since Diplomonads have modified mitochondria, what does that make them?

Answer 17

anaerobic organisms
(these organelles lack functional electron transport chains and hence cannot use oxygen to help extract energy from carbohydrates and other organic molecules)

Question 18

what is an example of a Diplomonad parasite?

SOS

Answer 18

Giardia intestinalis or Giardia Lamblia

Question 19

what does Giardia intestinalis cause?

SOS

Answer 19

it is a pathogenic parasite that causes gastroenteritis (food poisoning)

Question 20

how does the transmission of Giardia intestinalis (or the disease it causes - gastroenteritis) occur?

SOS

Answer 20

food-borne disease

Question 21

what are the characteristics of Parabasalids?

Answer 21

flagellated protozoa with modified mitochondria

Question 22

what is the type of modified mitochondria in Parabasalids?

SOS

Answer 22

hydrogenosomes
(because they produce hydrogen gas as a byproduct)

Question 23

what is an example of a Parabasalid parasite?

SOS

Answer 23

Trichomonas vaginalis

Question 24

what does Trichomonas vaginalis cause?

SOS

Answer 24

• causes vaginitis in women
• causes urethritis in men

Question 25

how does the transmission of Trichomonas vaginalis (or the disease it causes) occur?

Answer 25

sexually transmitted disease

Question 26

what are the morphological characteristics of Euglenozoans?

Answer 26

spiral or crystalline rod inside their flagella

Question 27

what are the two types of Euglenozoa?

Answer 27

- Kinetoplastids: include pathogenic species (e.g. trypanosomes) - Euglenids (non-pathogenic = don't need to know)

Question 28

what is a characteristic of Kinetoplastids?

Answer 28

have a single mitochondrion

Question 29

what is an example of pathogenic species in Kinetoplastids?

Answer 29

Trypanosomes

Question 30

the genus of trypanosomes contains 2 important pathogenic species, what are they?

Answer 30

(1) Trypanosoma Brucei (2) Trypanosoma Cruzi

Question 31

what does Trypanosoma Brucei cause?

Answer 31

causes sleeping sickness in humans (African trypanosomiasis)

Question 32

how is sleeping sickness in humans (African trypanosomiasis) transmitted?

Answer 32

transmitted by the tsetse fly (genus Glossina)

Question 33

what are the symptoms of sleeping sickness in humans (African trypanosomiasis)

Answer 33

CNS infection => lethargy, coma, death (therefore, known as sleeping sickness)

Question 34

what does Trypanosoma Cruzi cause?

Answer 34

causes Chagas' disease (American trypanosomiasis)

Question 35

how is Chagas' disease (American trypanosomiasis) transmitted?

Answer 35

transmitted by triatomine bugs (genus Triatoma)

Question 36

what are the symptoms of Chagas' disease (American trypanosomiasis)?

Answer 36

chronic myocardiopathy

Question 37

what two Excavates live in anaerobic environments?

Answer 37

diplomonads and parabasalids

Question 38

what does the supergroup SAR stand for/what groups does it include?

Answer 38

SAR = groups Stramenopiles, Alveolates, Rhizaria

Question 39

what are the characteristics of Alveolates?

Answer 39

have membrane-bound sacs (alveoli) underneath their plasma membrane

Question 40

what are the pathogenic species that Alveolates include?

Answer 40

Apicomplexans

Question 41

what are Apicomplexans?

Answer 41

pathogenic parasites that cause serious human disease

Question 42

how do Apicomplexans spread?

Answer 42

- 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

Question 43

what are the pathogenic species included in Apicomplexans?

Answer 43

(1) Plasmodium malariae (2) Toxoplasma gondii

Question 44

what does Plasmodium malariae cause?

Answer 44

malaria

Question 45

how is malaria transmitted?

Answer 45

by mosquitos

Question 46

describe the plasmodium life cycle and how it infects our body

Answer 46

infectious cells: - sporozoites: infect liver cells - merozoites: infect RBCs (& digest hemoglobin)

Question 47

explain what natural selection favors in areas with high prevalence of malaria

Answer 47

natural selection favored selective survival of the thalassemia allele carriers (heterozygotes) in areas with high prevalence of malaria

Question 48

what does Toxoplasma gondii cause?

Answer 48

toxoplasmosis

Question 49

how is toxoplasmosis transmitted?

Answer 49

(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

Question 50

what are the 2 groups of the Supergroup Unikonts?

Answer 50

(1) Amoebozoans (2) Opisthokonts

Question 51

what are the characteristics of Amoebozoans?

Answer 51

amoebas with lobe or tube shaped pseuodopodia

Question 52

what are the pathogenic species included in Amoebozoans?

Answer 52

Entamoebas (animal parasites/pathogens)

Question 53

what do the Opisthokonts include?

Answer 53

Animal, fungi, and 2 protist groups (non-pathogenic)

Question 54

what are the pathogenic species included in Entamoebas?

Answer 54

(1) Entamoeba histolytica: causes amebic dysentery (2) Acanthamoeba: contact lenses eye infection (keratitis, encephalitis

Question 55

a role of protists in ecological communities is pathogenicity; what are two examples of parasitic protists?

Answer 55

- Plasmodium malariae: causes malaria - Pfiesteria shumwayae: a dinoflagellate that causes fish kills