Structure of a euglena: flagellate freshwater protozoan. It is composed of chlorophyll and has a rudimentary eye.
Reservoir: part of a euglena used for storage.
Nucleus: central organelle of a euglena.
Contractile vacuole: cavity of the euglena that is able to contract.
Pellicle: membrane that envelops a euglena.
Chloroplast: organelle of the euglena responsible for photosynthesis.
Nucleolus: spherical body that contains the nucleus of a euglena.
Stigma: light-sensitive part of a euglena.
Flagellum: long, mobile filament used by the euglena for locomotion.