One of the ways to differentiate between plants and protists is by comparing the classification of some of the eukaryotes that belong to the two. Any photosynthetic eukaryote that belongs to the kingdom Plantae is known as a plant. On the other hand, protists are mostly eukaryotic unicellular organisms roughly grouped into the kingdom Protoctista.
It is believed that protists are different from one another that they are not fit to be grouped together as a kingdom. Another difference is that the nuclear DNA strands in plants are more complex than that of protists, and that is why it is very easy to differentiate between the various species of plants clearly. While all plants are multicellular organisms, most protists are unicellular organisms, though some are multicellular organisms. All plants are known as autotrophs since they produce their own food. However, some protists are also autotrophs, while others are heterotrophs.
You know what? I always used to think protists are also plants until recently that I came across the difference online. You might be like me too. But plants belong to a kingdom, while protists belong to different ones. In pants cells, the nuclear DNA strands have higher complexity compared to those in protists. In addition, all plants are multi-cellular, which is unlike protists.
Conversely, some of the protists are unicellular, while even some others live in colonies, performing some tasks together, such as movement and feeding. And still, you need to be informed that even when some of these protists are unicellular, some others are multi-cellular; a typical example is a seaweed.
As though in science, plants are referred to as autotrophs or primary producers, that means they produce food through inorganic molecules. But in the case of protists, while some are autotrophs, such as algae, others are heterotrophs or consumers.