Difference between a unicellular protoctist and bacterium?

Unicellular protoctists are eukaryotic organisms that can be photosynthetic, heterotrophic, or mixotrophic in nature, while bacteria are prokaryotic organisms. Protoctists have a nucleus and other organelles enclosed in a membrane, whereas bacteria lack a defined nucleus and organelles. Additionally, bacteria have a cell wall composed of peptidoglycan, while protoctists may have cell walls made of various materials or lack them altogether.