Streptococcus is a prokaryote (bacterium) and therefore completely lacks membrane-bound organelles such as mitochondria, endoplasmic reticulum, Golgi apparatus, and nucleus. Plasmodium is a eukaryotic parasite; Saccharomyces is a eukaryotic yeast; Chlamydomonas is a eukaryotic green alga — all have membrane-bound organelles.