Topic 7A: Protists ✅ Flashcards Preview

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Flashcards in Topic 7A: Protists ✅ Deck (55)
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1
Q

Domain Eukarya’s kingdoms

A
  1. Protists
  2. Fungi
  3. Plants
  4. Animals
2
Q

Protists are mostly..

A

Unicellular eukaryotic microorganisms

3
Q

Protist types

A

Protozoa (e.g. Amoebas)

Algae (e.g. seaweeds)

4
Q

Fungi are mostly

A

Unicellular or multicellular eukaryotic microorganisms

5
Q

Fungal types

A

Yeasts
Eg unicellular fungi (S. cerevisiae)

Multicellular fungi
Eg mushrooms, molds

6
Q

Protozoa

A

No cell wall
No chlorophyll

Mostly unicellular

Several pathogenic species → eukaryotic parasites
Eg amoeba

7
Q

Algae

A

Cell wall
Chlorophyll

Photosynthetic organisms

Some are unicellular (eg seaweeds)

8
Q

Properties of protists

A

Most unicellular

Some multicellular or can form multicellular colonies

Motility: cilia or flagella

Reproduction: asexual or sexual

Various nutritional modes: photoautotrophs, heterotrophs, mixotrophs.

9
Q

Photoautotrophs

A

Contain chloroplasts

Perform photosynthesis

10
Q

Heterotrophs

A

Absorb organic molecules or ingest larger food particles (by phagocytosis)

11
Q

Mixotrophs

A

Combine photosynthesis and heterotrophic nutrition

12
Q

Supergroups of Eukarya

A
  1. Excavates
  2. SAR
  3. Archaeplastids
  4. Unikonts
13
Q

SAR has..

A

Chromalveolates

Rhizarians

14
Q

Excavata

A

Characterized by presence of feeding groove in some

Diplomonads (Giardia intestinalis)
Parabasalids (Trichomonas vaginalis)

Euglenozoans (Trypanosomes)

15
Q

Diplomonads example

A

Eg Giardia intestinalis (Giardia lamblia)

Characteristics: flagellated Protozoa with modified mitochondria (mitosomes)

Pathogenic parasite: causes gastroenteritis (food poisoning)

Transmission: food-borne disease

16
Q

Parabasalipids example

A

Eg Trichomas vaginalis

Characteritistics: flagellated Protozoa with modified mitochondria (hydrogenosomes)

Pathogenic parasite, causes vaginitis in women, urethritis in men

Sexually transmitted disease

17
Q

Euglenozoans example

A

Eg Trypanosomes

Morphological characteristic: spiral or crystalline rod inside their flagella

Euglenozoa:
Kinetoplastids- includes pathogenic species, have a single mitochondrion
Euglenids- non-pathogenic

18
Q

Trypanosoma brucei

A

Pathogenic

Causes sleeping sickness in humans (African trypanosomiasis)

-transmitted by the tsetse fly (genus Glossina)

-CNS infection -> lethargy, coma death

19
Q

Trypanosoma cruzi

A

Pathogenic

Causes Chagas’ disease (American trypanosomiasis)

-transmitted by triatomine bugs (genus Triatoma)

-symptoms: chronic myocardiopathy

20
Q

SAR

A

Stramenopiles & Alveolates, Rhizaria

21
Q

Chromalveolates

A

Alveolates

Stramenopiles

22
Q

Alveolates

A

Have membrane-bounded sacs (alveoli) underneath their plasma membrane

Include:
Apicomplexans: contains pathogenic species
Dinoflagellates
Ciliates

23
Q

Apicomplexans

A

Pathogenic parasites, some cause serious human diseases

Spread through host cell as infectious cells called sporozoites

Apex contains organelles specialized for penetrating host cells and tissues

Require 2+ different host species for completion of life cycle

Eg Plasmodium malariae (causes malaria) and Toxoplasma gondii (causes toxoplasmosis)

24
Q

Plasmodium malariae

A

Apicomplexan (pathogenic parasite)

Causes malaria

Transmitted by mosquitoes
-> reproduced in the RBC leading to haemoglobin digestion

->natural secretion favored selective survival of the thalassaemia allele carriers in areas with high prevalence of malaria

900,000 deaths/year

Ongoing efforts for vaccine development

25
Q

Toxoplasma gondii

A

Apicomplexan

Causes toxoplasmosis

Transmission:
1. Oral-faecal route:
-by consuming contaminated raw/undercooked meat
-by ingesting anything contaminated with cat or other animal faeces

  1. Trans-placental transmission:
    -from mother to foetus
    -can cause abortion , hydrocephalus, mental retardation
26
Q

Sporozoites

A

Infect liver cells

27
Q

Merozoites

A

Infect RBC

28
Q

Ciliates

A

Use cilia to move and feed

Eg paramecium- ciliated protozoon

29
Q

Ciliates morphology

A

Cilia

Oral groove

Cell mouth

Food vacuoles

Macronucleus

Micro nucleus

Contractile vacuole

30
Q

What are stramenopiles characterized by?

A

Presence of smooth or hairy flagella

31
Q

Stramenopiles ->

A

Diatoms

Golden algae
Brown algae
Oomycetes

32
Q

Dinoflagellates and Diatoms

A

Dinoflagellates: 2 flagella (in Alveolates)

Diatoms: photosynthetic protists, unicellular (in Stramenopiles)

Major components of phytoplankton

33
Q

Golden algae and Brown algae

A

Golden: unicellular (form multicellular colonies)

Brown: multicellular algae

34
Q

Oomycetes

A

Stramenopile

Water molds and their relatives

Initially considered fungi, based on morphological studies
-phylogenetic analysis categorized the under Parasites

Most are decomposers or parasites

Eg Phytophthora infestans: causes potato blight

Phtophthora ramorum: causes oak death

35
Q

Rhizaria ->

A

Cercozoans
Forams

Radiolarians

36
Q

Rhizaria

A

Includes several types of amoebas with threadlike pseudopodia

Eg Globigernina

37
Q

Pseudopodia

A

Cytoplasmic projections

-role in motility and phagocytosis

38
Q

Archaeplastids

A

Includes plants and some protists groups

Protist groups:
-Red algae and
-Green algae - Chlorophtes and Charophytes

39
Q

Archaeplastids ->

A

Red Algae

Green Algae:
-Chlorophtes
-Charophytes

-Land plants

40
Q

Red Algae

A

Red colour due to phycoerythrin pigment

Eg tropical seaweeds

Bonnemaisonia hamifera, Dulse (Palmaria palmata), Nori.

41
Q

Green Algae

A

Chlorophtes, Charophytes

Eg
Ulva (sea lettuce)

Caulerpa (an intertidal chlorphyte)

Volvox (a colonial freshwater green algae)

42
Q

Unikonts

A

Supergroup 4

2 groups:
Amoebozoans

Opisthokonts

43
Q

Amoebozoans->

A

Slime molds

Gymnamoebas

Entamoebas

44
Q

Amoebozoans

A

In Unikonts
Amoebas with lobe or tube shaped pseudopodia

Slime molds

Gymnamoebas: in aquatic environments

Entamoebas: includes pathogenic species

45
Q

Opisthokonts

A

In Unikont supergroup

Animals, fungi, 2 Protist groups

Protist groups: Nucleariids, Choanoflagellates

46
Q

Structure of an Amoeba

A

Pseudopodium

Cell membrane

Ectoplasm

Endoplasm

Nucleus

Food vacuole
Digestive vacuole
Contractile vacuole

47
Q

Entamoebas

A

Amoebozoa group in Unikont Supergroup

Animal parasites (pathogens)

Eg Entamoeba histolytica: causes amebic dysentry
-3rd leading cause of human death due to eukaryotic parasites
-stomach ulcers

Acanthamoeba: contact lenses eye infection (keratitis), encephalitis

48
Q

Role of protists in ecological communities: symbiotic protists

A

Dinoflagellates: role in development of reeefs

Wood-ingesting protists: digest cellulose in the gut of termites

49
Q

Role of protists in ecological communities: Phtotsynthetic protists

A

Major energy producers in aquatic environments

50
Q

Role of protists in ecological communities: Pathogenic Protists

A

Parasite protists

Plasmodium malaria: causes malaria

Pfiesteria shumwayae: dinoflagellate that causes fish kills

51
Q

Eukaryotes (domain) -> ____ (Supergroups) -> ___ (groups)

A

Excavates -> Several protist groups (Parabasalids, Diplomonads, Euglenozoans)

SAR -> Several Protist groups (Stramenopiles, Alveolates, Rhizarians)

Archaeplastids -> 2 Protist groups (Red and Green algae) and Plant [Kingdom]

Unikonts -> Several Protist groups, Fungi and Animal [Kingdoms]

52
Q

What are Chromalveolates and Rhizarians classified together as?

A

The supergroup SAR clade

53
Q

Where may Chromalveolates have originated from?

A

By secondary endosymbiosis

54
Q

Supergroup -> Major groups -> key morphological features -> specific examples

A

Excavates ->Diplomonads and parabasalids
-> modified mitochondria
-> Giardia, Trichomanas

Excavates -> Euglenozoans (Kinetoplastids, Euglenids)
-> Spiral or crystalline rod inside flagella
-> Trypanosoma, Euglena

SAR (Chromalveolates) -> Alveolates (Dinoflagellates, Apicomplexans, Ciliates)
-> Membrane-bounded sacs (alveoli) beneath plasma membrane
-> Pfiesteria, Plasmodium, Paramecium

SAR (Chromalveolates) -> Stramenopiles (Diatoms, Golden Algae, Brown Algae, Oomycetes)
-> Hairy and smooth flagella
-> Phytophthora, Laminaria

SAR (Rhizarians) -> Radiolarians
-> Amoeba with threadlike pseudopodia radiating from central body
-> Hexacontium

SAR (Rhizarians) -> Forams
-> Amoebas with threadlike pseudopodia and a porous shell
-> Globigerina

SAR (Rhizarians) -> Cercozoans
-> Amoebas and flagellated protists with threadlike pseudopodia
-> Paulinella

Archaeplastida -> Red algae
-> Phcoerythrin (accessory pigment)
-> Porphyra

Archaeplastida -> Green Algae
-> Plant-type chloroplasts
-> Chlamydomonas, Ulva

Archaeplastida -> Land Plants
-> ———————
-> Mosses, ferns, conifers, flowering plants

Unikonts -> Amoebozoans (Slime molds, Gymnamoebas, Entamoebas)
-> Amoebas with lobe-shaped pseudopodia
-> Amoeba, Entamoeba, Dictyostelium

Unikonts -> Opisthokonts
-> ———
-> Nucleariids, choanoflagellates, animals, fungi

55
Q

Humans pathogenic Protists

A

Giardia Intestinalis (giardia lamblia) -> gastroenteritis (food poisoning)
-> diplomonad

Trichomonas vaginalis -> vaginitis (women) and urethritis (men)
-> Parabasalid

Trypanosoma brucei -> African tryptanosomiasis (sleeping disease) -> Kinetoplastid Euglenozoan

Trypanosome cruzi -> American trypanosomiasis (Chagas’ disease)
-> Kinetoplastid Euglenozoan

Plasmodium malariae -> Malaria
-> Apicomplexan Alveolate

Toxoplasma gondii -> Toxoplasmosis
-> Apicomplexan Alveolate

Entamoeba histolytica -> Amebic dysentry
-> Entamoeba amoebozoan

Acanthamoeba -> Eye infection, encephalitis
-> Entamoeba amoebozoan