Topic 7: eukaryotic microorganism protists + fungi

Question 1

Describe protists

Answer 1

• Unicellular eukaryotic microorganisms
  TYPES:
  1) Protozoa e.g. amoebas
  2) Fungi e.g. seaweeds

Question 2

Describe fungi

Answer 2

• Uni/multicellular eukaryotic microorganisms
  TYPES:
  1) Yeasts = unicellular e.g. S.cerevisiae
  2) Multicellular fungi e.g. mushroom/mold

Question 3

Describe protozoa

Answer 3

• No cell wall + chlorophyll
• Unicellular
• Pathogenic species = parasites
• E.g. amoebas

Question 4

Describe algae

Answer 4

• Cell wall + chlorophyll
• Photosynthetic
• Some species multicellular
• E.g. seaweeds

Question 5

Give properties of protists

Answer 5

• Can form multicellular colonies
• Mobility = cilia/flagella
• Reproduction = asexual/sexual
• Many nutritional modes

Question 6

Give the nutritional modes of protists

Answer 6

1) Photoautotrophs: chloroplasts = photosynthesis
2) Heterotrophs: absorb organic molecules + ingest food va phagocytosis
3) Mixotrophs: combinations of 1+2

Question 7

4 supergroups of Eukarya

Answer 7

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

Question 8

Describe supergroup excavates

Answer 8

• Have a feeding groove
  SUBGROUPS
  1) Diplomonads = e.g. Giardia intestinalis
  2) Parabasalids = e.g. Trichomonas vaginalis
  3) Euglenozoans = e.g. Trypanosomes

Question 9

Describe diplomonads

Answer 9

• Protozoa
• Characteristics = flagellated + modified mitochondria
• Pathogenic parasite = gastroenteritis
• Transmission = food-borne

Question 10

Describe parabasalids

Answer 10

• Protozoa
• Charcteristics = flagellated + modified mitochondria
• Pathogenic parasite = vaginitis in women + urethritis in men
• Transmission = sexually

Question 11

Describe euglenozoans

Answer 11

• Characteristics = spiral/crystalline rod inside flagella
  TYPES:
  1) Kinetoplastid = pathogenic species e.g. trypanosomes
  2) Euglenids = non-pathogenic

Question 12

Describe kinetoplastids

Answer 12

• Single mitochondrion
  SPECIES:
  1) Trypanosoma brucei = sleeping sickness = African varient
• Transmitted via tsetse fly
• Symptoms = CNS infection = lethargy + coma + death
  2) Trypanosoma cruzi = Chagas disease = American varient
• Transmitted via triatomine bugs
• Symptoms = chronic myocardiopathy

Question 13

What groups are in supergroup SAR?

Answer 13

1) Stramenopiles
2) Alveolates
3) Rhizaria

Question 14

Describe alveolates

Answer 14

• Membrane-bound sacs under plasma membrane = alveoli
  TYPES:
  1) Apicomplexans
  2) Dinoflagellates
  3) Ciliates

Question 15

Describe apicomplexans

Answer 15

• Pathogenic parasites
• Spread via host = as infectious cells called sporozoites
• Apex = organelles for penetrating host cell/tissue
• Need 2+ host for life cycle completion
  SPECIES:
  1) Plasmodium malariae = malaria
  2) Toxoplasma gondii = toxoplasmosis

Question 16

Describe plasmodium malariae

Answer 16

• Causes malaria
• Transmission = mosquitoes
• Reproduction = in RBC = haemoglobin digestion
• Natural selection favoured = survival of the
  thalassaemia allele carriers = areas with high malaria prevalence
• 900,000 deaths/year from malaria
• Vaccine developing

Question 17

Describe Toxoplasma gondii

Answer 17

• Causes toxoplasmosis
• Transmission:
  > Oral-faecal = injesting contaminated raw/undercooked meat + anything contaminated with cat/animal faeces
  > Trans-placental transmission = mother > fetus = can cause abortion + hydrocephalus + retardation

Question 18

Describe ciliates

Answer 18

• Use cilia to move + feed
• E.g. Parmecium

Question 19

Describe Stramenopiles

Answer 19

• Have smooth/hairy flagella

Question 20

Describe dinoflagellates

Answer 20

• Have 2 flagella
• Part of alveolates
• Major component of phytoplankton

Question 21

Describe diatoms

Answer 21

• Photosynthetic protists
• Part of stramenopiles
• Major component of phytoplankton

Question 22

Describe oomycetes

Answer 22

• Water molds
• Initially = fungi-based morphologically > phylogenetic analysis = protists
• Decomposers + parasites
• E.g. Phytophthora infestans =causes potato blight
• E.g. Phytophthora ramorum = causes oak death

Question 23

Describe rhizaria

Answer 23

• Amoebas with threadlike pseudopodia
• E.g. marine/freshwater amoebas

Question 24

Define pseudopodia

Answer 24

• Cytoplasmic projections
• Role = motility + phagocytosis

Question 25

Describe supergroup archaeplastids

Answer 25

- Includes plants + protists - Protists included: > Red algae > Green algae

Question 26

Describe red algae

Answer 26

- Color due to = phycoerythrin pigment - E.g. tropical seaweed

Question 27

Give the 2 types of green algae

Answer 27

1) Chlorophytes 2) Charophytes

Question 28

Give the 2 groups of supergroup unikonts

Answer 28

1) Amoebozoans 2) Opisthokonts

Question 29

Describe amoebozoans

Answer 29

- Amoebas with lobe/tube-shaped pseudopodia TYPES: 1) Slime molds 2) Gymnamoebas = aquatic environment 3) Entamoebas = pathogenic species

Question 30

Describe entamoebas

Answer 30

- Animal parasites = pathogens TYPES: 1) Entamoeba histolytica = causes amebic dysentry + 3rd leading cause of death due to eukaryotic parasite 2) Acanthamoeba = contact lenses eye infection + encephalitis

Question 31

Describe opisthokonts

Answer 31

- Animals/fungi/2 protist groups 2 PROTIST TYPES: 1) Nucleariids 2) Choanoflagellates

Question 32

Explain the role of protists in ecological communities

Answer 32

- As symbiotic/photosynthetic protists SYMBIOTIC: - Dinoflagellates = development of coral reefs - Wood-digesting protists = digest cellulose in gut of termites PHOTOSYNTHETIC: - Major energy producer in aquatic environment - Pathogenic parasitic protists = Plasmodium malaria + Pfiesteria shumwayae = dinoflagellate that causes fish kills