Trophozoite

Definition

A trophozoite is the active, feeding, and growing stage of a protozoan parasite. It contrasts with other life cycle stages such as cysts, which are dormant and resistant.

5 Must Know Facts For Your Next Test

1. Trophozoites are typically found in host tissues or fluids where they actively feed and reproduce.
2. They can be identified microscopically by their motility and distinctive morphology.
3. During adverse conditions, trophozoites often transform into cysts to survive outside the host.
4. Common diseases involving trophozoites include malaria (Plasmodium spp.) and amoebiasis (Entamoeba histolytica).
5. Diagnosis of infections often involves detecting trophozoites in clinical samples like blood smears or stool samples.

Review Questions

• What is the primary function of a trophozoite in the life cycle of protozoan parasites?
• How do trophozoites differ from cysts in terms of morphology and function?
• Name two diseases where the presence of trophozoites is a key diagnostic feature.

Related terms

Cyst:

A dormant, resistant stage of some protozoan parasites that aids in survival outside the host.

Protozoa:

Single-celled eukaryotic organisms, often parasitic, that can cause various diseases.

Sporozoite: A motile spore-like stage in the life cycle of some parasitic protozoa, including those causing malaria.