Streptacaccus is a spherical, Gram-positive bacterium. Membrane bound organelles are absent in prokaryotes. Fungi (eg, Saccharomyces) represents a group of eukaryotic, non-photosynthetic, heterotrophic organisms. Algae (eg, Chlamydomonas) is a group of chlorophyll bearing, autotrophic, thalloid plants. Plasmodium is a genus of protists. Infection by these organisms is known as malaria.