Apical complex

Definition

The apical complex is a specialized structure found in certain unicellular eukaryotic parasites, specifically those within the phylum Apicomplexa. It facilitates host cell invasion through a combination of secretory organelles and cytoskeletal elements.

5 Must Know Facts For Your Next Test

1. The apical complex contains structures such as rhoptries, micronemes, and polar rings that are essential for host cell penetration.
2. Apicomplexans like Plasmodium (which causes malaria) and Toxoplasma gondii utilize the apical complex for infecting host cells.
3. The apical complex is not present in all stages of the parasite's lifecycle; it is typically prominent during invasive stages like sporozoites and merozoites.
4. Drugs targeting components of the apical complex show potential for treating diseases caused by Apicomplexan parasites.
5. The formation and function of the apical complex are regulated by calcium signaling pathways.

Review Questions

Related terms

Rhoptries:

Organelles within the apical complex involved in secreting enzymes that facilitate host cell invasion.

Micronemes:

Small secretory organelles in the apical complex that release proteins aiding parasite attachment to host cells.

Apicoplast:

A non-photosynthetic plastid found in most Apicomplexa, crucial for fatty acid synthesis and other metabolic functions.