protista

Question 1

what are protista?

Answer 1

eukaryotes that are neither plants, animals or fungi

Question 2

4 supergroups of eukarya

Answer 2

Excavata, SAR, Archaeplastida, Unikonta

Question 3

features of protista

Answer 3

eukaryotic, lack highly specialised tissues, mostly unicellular, diverse, paraphyletic

Question 4

what are protozoa?

Answer 4

unicellular heterotrophic protists

Question 5

Protist roles

Answer 5

keystone organisms of soil ecosystems, and regulate essential processes of soil fertility such as nutrient cycling and plant growth

Question 6

Excavata

Answer 6

excavated groove on one side in some

Question 7

Unikonta

Answer 7

have single emergent flagellum or are amoeba with no flagella
related to fungi and animals

Question 8

SAR

Answer 8

3 large, diverse clades with DNA similarities
- Stramenoplia
- Alveolata
- Rhizaria

Question 9

Archaeplastida

Answer 9

red and green algae
arose through primary endosymbiosis
related to plants

Question 10

3 Excavata groups

Answer 10

Diplomonads
Parabasilids
Euglenozoans

Question 11

What are Diplomonads? Give an example

Answer 11

Phylum in Excavata supergroup with modified mitochondria and 2 equal-sized nuclei.
Small cells (~10 µm) with characteristic
doubled organisation and multiple flagella
Many are parasitic

eg. Giardia

Question 12

What are Parabasilids? Give an example

Answer 12

Phylum in Excavata supergroup with modified mitochondria and an undulating membrane for locomotion.
anaerobic
all are endosymbionts with animals

eg. trichomonas

Question 13

Euglenozoans

Answer 13

phylum in Excavata supergroup with spiral or crystalline rod inside flagella

Question 14

SAR clade, 3 end-tree groups and feature

Answer 14

Clade = Alveoaltes
groups = Dinoflagellates, Apicomplexans, Ciliates
Feature= Have membrane-enclosed sacs (alveoli) beneath plasma membrane

Question 15

Unikonta clade, 3 end-groups and feature

Answer 15

Clade = Amoebazoans
groups = Tubulinids, slime molds and Entamoebas
Feature = Amoebas with lobe-shaped or tube-shaped pseudopodia

Question 16

What are Kinetoplastids? Give 2 examples

Answer 16

Group of flagellated protists in Euglenozoa phylum (Excavata) containing a single, large mitochondrion, and a kinetoplast, a granule containing an organised mass of DNA

eg. - Trypanosoma, Leishmania

Question 17

What are Apicomplexans? Give 2 examples

Answer 17

Organisms in Alveolata phylum (SAR), mostly parasitic

eg. Plasmodium, Cryptosporidium

Question 18

What are Entamoebas? Give 2 examples

Answer 18

genus of Amoebazoa phylum (Unikonta)

eg. Entamoeba, Naegleria

Question 19

common features of Diplomonads and Parabasilids

Answer 19

Highly reduced mitochondria that lack DNA, e- transport chain and enzymes of citric acid cycle –> adapted for anaerobic metabolism and environments

Question 20

Giardia Intestinalis/Duodenalis - what is it? what are the symptoms?

Answer 20

common intestinal parasite
Symptoms: diarrhoea, dehydration and intestinal pain

Question 21

Giardia Intestinalis/Duodenalis - Mechanism of infection (What route?
Is a vector organism involved?)

Answer 21

Contamination of water, food or hands by infective cysts, ingested by human. No vector organism, just host.

Question 22

Giardia Intestinalis/Duodenalis - Mechanism of the disease (What
part of the human body is affected?
How?)

Answer 22

Coat intestinal wall and feed on mucous secretions, affecting absorption of fatty acids

Question 23

Giardia Intestinalis/Duodenalis - How can it be diagnosed?

Answer 23

Diagnosis is by identification of cysts or trophozoites in the faeces

Question 24

Giardia Intestinalis/Duodenalis - Infective life stages

Answer 24

Only cysts are infective – the trophozoites do not survive in the environment, whereas cysts can remain viable for week to months.

Question 25

Trophozoite

Answer 25

A stage in the life cycle of some protist parasites when they absorb nutrients from the host.

Question 26

Cyst

Answer 26

A life cycle stage of a protist parasite with a protective membrane or thickened wall.

Question 27

Trichomonas vaginalis - what is it?

Answer 27

parasite of Parabasilid phylum (Excavata) inhabiting reproductive and urinary tract of men and women

Question 28

Trichomonas vaginalis - Mechanism of infection

Answer 28

sexual intercourse

Question 29

Trichomonas vaginalis - Mechanism of the Disease & Symptoms

Answer 29

Causes infection when acidity of the vagina is disturbed (trichomoniasis): capillary
haemorrhage

• asymptomatic in males
• burning during urination for females

Question 30

Trichomonas vaginalis - Diagnosis

Answer 30

cervical smear

Question 31

Trichomonas vaginalis - Infective and diagnostic life stages

Answer 31

*Trophozoite is the only life-stage form, it cannot encyst (poor survival outside of the host)

1. Diagnosable but not infective as trophozoite in vaginal and prostatic secretions and urine.
2. Multiplies by binary fission
3. Becomes infective trophozoite in vagina or urethra

Question 32

Trypsanoma cruzi - what is it?

Answer 32

parasitic protozoan in Euglenozoan phylum (Excavata), causes ‘Sleeping Sickness’

Question 33

Trypsanoma cruzi - Mechanism of infection

Question 34

Trypsanoma cruzi - Diagnosis

Answer 34

Diagnosed microscopically in blood and other body fluids.

Question 35

Trypsanoma cruzi - Mechanism of Disease & Symptoms

Answer 35

Symptoms depend on the species of Trypanosome – in humans, a vascular and
lymphatic infection is followed by an invasion of the central nervous system that gives rise to ‘sleeping’ symptoms, followed by death.

Question 36

Trypsanoma cruzi - Infective and diagnostic life stages

Question 37

epimastigote

Answer 37

replicative stage in the invertebrate host

Question 38

trypomastigote

Answer 38

replicative stage in the mammalian host, main infective stage

Question 39

metacyclic

Answer 39

Infective stage
outside the host body

Question 40

what does ‘mastigote’ mean?

Answer 40

bearing flagella