| Pseudopod | A temporary, foot-like extension of a cell, used for locomotion or engulfing food. |
| Nucleus | The region of a eukaryotic cell that contains the cell's main DNA. |
| Vacuole | A membrane-bounded "sac" within a cell. |
| Ectoplasm | The thin, watery cytoplasm found in the interior of many cells. |
| Endoplasm | The dense cytoplasm found in the interior of many cells. |
| Flagellate | A protozoan that propels itself with a flagellum. |
| Pellicle | A firm, flexible coating outside the plasma membrane. |
| Chloroplast | An organelle containing chlorophyll for photosynthesis. |
| Chlorophyll | A pigment necessary for photosynthesis. |
| Eyespot | A light-sensitive region in certain protozoa. |
| Symbiosis | A close relationship between two or more species where at least one benefits. |
| Mutualism | A relationship between two or more organisms of different species where all benefit from the association. |
| Commensalism | A relationship between two organisms of different species where one benefits and the other neither harmed or benefited. |
| Parasitism | A relationship between two organisms of different species where one benefits and the other is harmed. |
| Cilia | Hairlike projections that extend from the plasma membrane and are used for locomotion. |
| Spore | A reproductive cell with a hard, protective coating. |
| Plankton | Tiny organisms that float in the water. |
| Zooplankton | Tiny floating organisms that are with small animals or protozoa. |
| Phytoplankton | Tiny floating photosynthetic organisms, primarily algae. |
| Thallus | The body of a plant-like organism that is not divided into leaves, roots, or stems. |
| Cellulose | A substance (made of sugars) that is common in the cell walls of many organisms. |
| Holdfast | A special structure used by an organism to anchor itself. |
| Sessile Colony | A colony that uses holdfasts to anchor itself to an object. |
