Plasmodium is a genus of unicellular eukaryotic parasites that includes the organisms causing malaria. Its members have a cell nucleus and specialized organelles; they are not bacteria. In the malaria life cycle, multiplication in a vertebrate host alternates with development in a mosquito vector. Different stages occupy different host environments.
Many malaria parasites retain an apicoplast, an organelle descended from a plastid. A blood-stage study connected its essential role to production of isoprenoid precursors: replacing the missing metabolic output could bypass organelle loss in that experimental context. [ref]
Chemical rescue of malaria parasites lacking an apicoplast defines organelle function in blood-stage Plasmodium falciparum by Ellen Yeh and others. 2011, abstract: apicoplast loss and identification of essential isoprenoid-precursor production in the asexual blood stage
The result concerns a defined life stage and does not imply that every organelle function is dispensable throughout the parasite's life cycle. New to topics? Read the docs here!