Lecture 6 - Intestinal Flagellate

Question 1

Intestinal parasite that bears 4 flagella, nonpathogenic and transmitted in cyst stage in feces

Answer 1

Order Retortamonadida

Chilomastix mesnili

Question 2

Trophozoite - bears 2 flagella (4-9 um long) and is harmless (commensal)

Answer 2

Retortamonas intestinalis

Question 3

Intestinal flagellate that is binucleate and lacks mitochondria, smooth ER, Golgi. and lysosomes

Answer 3

Order Diplomonadida

Giardia spp.

Question 4

GIardia species that is the most common flagellate of the human digestive system, usually in the small intestine

Answer 4

Giardia lamblia (G. Intestinallis, G. Doudinalis)

Question 5

Physical characteristics of Giardia Lamblia

Answer 5

o	Troph. - 12-15 um long
o	Ventral surface concave
o	Adhesive disc – attachment to host cells
o	Tear-drop shaped
o	2 nuclei
o	Four pairs of flagella

Question 6

How does Giardia lamblia reproduce?

Answer 6

longitudinal/binary fission

Question 7

How many nuclei do new cysts have?

Answer 7

2

Question 8

How many nuclei do old cysts have?

Answer 8

4

Question 9

Life cycle of G. lamblia

Answer 9

• Cysts pass with feces
• Infection by ingesting cyst
• Excyst in duodenum and mature

Question 10

Metabolism of G. lamblia

Answer 10

•	Aerotolerant anaerobe
•	Lacks mitochondria
o	No Krebs cycle or electron transport
•	Produce CO2, ETOH, and acetate
o	More ETOH when no O2