Protozoan

Question 1

General characteristics of AMoeba

Answer 1

Characterized by the presence of hyaline foot-like extrusions
from the ectoplasm (pseudopods)
• Amoebas are very slow
• All amoebas are intestine dwellers except: E. gingivalis
All are commensals except: E. histolytica
Cyst is the infective stage except: E. gingivalis

From Phylum Sarcomastigophora (old), now Phylum
Amoebazoa
o Sarcomastigophora: combination of Sarcodina and
Mastigophora
§ Contains amoeba and flagellates

Question 2

All amoebas are intestine dwellers except:

Answer 2

E. gingivalis

Question 3

All are commensals except:q

Answer 3

E. histolytica

Question 4

Cyst is the infective stage except:

Answer 4

E. gingivalis

Question 5

Phylum Amoebazoa is formerly known as

Answer 5

Sarcomastigophora combination of Sarcodina and Mastigophora

Includes amoeba and flagellates

Question 6

4 STAGES IN THE LIFE CYCLE

Answer 6

Trophozoite
Pre-cystic stage
Cyst
Metacystic stage

Question 7

Trophozoite stage is

Answer 7

Vegetative Stage (feeding stage), motile stage,
labile stage

Question 8

Pre-cystic stage is

Answer 8

intermediary stage between trophozoite and cystic stage

Uninucleated

Question 9

A trophozoite that firstly transformed into the cystic stage

Answer 9

Pre-cystic stage

Question 10

CYSTIC STAGE is

Answer 10

Non-feeding stage, non-motile stage, resistant stage, infective stage

Question 11

METACYSTIC STAGE is

Answer 11

Stage that will develop to become the trophozoite

Stage wherein the cyst is near becoming a trophozoite

Question 12

Encystation

Answer 12

process when trophozoite transforms into a

cyst

Question 13

Excystation

Answer 13

• process when a cyst transforms into a

trophozoite

Question 14

False feet

Answer 14

Pseudopodium

Question 15

T or F : a typical cyst, the nuclei found in the trophozoite is
almost the same as found in the cyst

Answer 15

True

Question 16

Chromatoid bodies/Chromatoidal bars: are

Answer 16

aggregates of ribosomes

usually found in cysts

Question 17

Only pathogenic intestinal amoeba

• Super diagnosed and under diagnosed:

Answer 17

E. histolytica

Question 18

Most Pathogenic amoeba; true pathogen

Answer 18

E. histolytica

Question 19

Pathogenicity of E. histolytica means

Answer 19

ability to cause invasive intestinal amoebiasis or Extraintestinal amoebiasis

Question 20

Extraintestinal amoebiasis means

Answer 20

it can infect LIVER

Question 21

Habitat, Final host, MOT of E. histolytica

Answer 21

Large intestine
Man
Ingestion of mature cyst

Question 22

E. histolytica
Infective stage:
Virulent stage:

Answer 22

Infective stage: Cyst

Virulent stage: Trophozoite

Question 23

Max nuclei of E. histolytica

Answer 23

4 nuclei (quadrinucleated / tetranucleated)

Question 24

How to differentiate E. histolytica from E. dispar

Answer 24

only E. histolytica is hematophagous

Question 25

Characteristics of E. histolytica Cyst

Answer 25

Round/oval in shape
Thin cell wall
Evenly distributed peripheral chromatin
Centrally karyosome
Chromatoidal bodies are cigar shape with round ends
Maximum of 4 nuclei
Size range : 10-20 um (12-15um)

Question 26

apparatus placed in microscope to measure parasites

Answer 26

ocular micrometer

Question 27

Characteristics of E. histolytica trophozoite

Answer 27

Motility : progressive/aggressive/rapid directional with hyalin fingerlike pseudopods
Motile / vegetative / labile stage
Hematophagia 
Evenly distributed peripheral chromatin
Centrally karyosome
UNINUCLEATED
Finely granular "ground glass appearance" "clean looking" CYTOPLASM
Size range: 12-60um (15-20um)

Question 28

Same morphological features as that of E. histolytica

Answer 28

E. dispar
E. bangladeshi
E. moshkovskii

Question 29

E. histolytica diagnosis

Answer 29

1. DFS
2. Concentration technique
3. Culture media
4. Stains (Iodine for cyst ; Methylene blue for trophozoites)
5. Serological tests (antibody and antigen)

Question 30

E. coli is

Answer 30

a commensal

non pathogenic lumen/intestinal dweller

Question 31

MOT of E.coli

Answer 31

ingestion of cysts from contaminated water or food

Question 32

characteristics of E. coli cyst

Answer 32

Spherical/oval
Max of 8 nuclei
Eccentric and large karyosome
Coarsely granular/clumpedand unevenly distributed peripheral chromatin
Chromatoidal body is splinter shaped with rough pointed ends
Size range= 10-35um (15-25um)

Question 33

Maximum number of E. coli nuclei

Answer 33

8 nuclei

Question 34

Difference of E. histolytica and E. coli

Answer 34

E histolytica has evenly distributed peripheral chromatin

E. coli has coarsely granular unevenly distributed peripheral chromatin

E. histolytica has centrally located karyosome

E. coli has large and eccentrically located karyosome

E. histolytica has chromatoidal body in cigar shape with rounded ends

E. soli has splinter shaped chromatoidal body with rough pointed ends

Question 35

Characteristics of E. coli trophozoite

Answer 35

Motility: sluggish, nondirectional with blunt and granular pseudopodia
Mononucleated
Large not compacted eccentrically located karyosome
unevenly distributed clumped peripheral chromatin
Granular cytoplasm usually vacuolated contains debris
Dirty looking
Size ranged = 15-50um (20-25um)