Are Protists Bacteria? 7 Comprehensive Facts You Should Know

In this article we are focusing on the topic “Are Protists Bacteria? 7 Comprehensive Facts You Should Know”, with the detailed facts and explanations.

Protists are single celled or unicellular organisms that belongs to the Protista Kingdom. They are eukaryotic organisms that does not fall under plants, animals or fungi group. Though unicellular they can also be found growing in the colonies. Bacteria are single celled prokaryotes which are present everywhere and are the most abundantly found microorganisms.

Bacteria do not contain well defined organelles and has been classified as coccus, bacillus, vibrio and spirillum based on their shapes. Bacteria has been classified broadly as archaebacteria and eubacteria. Protists are primarily found in aquatic regions, they are heterotrophic, autotrophic and sometimes both. Their mode of reproduction is both asexual and sexual. Examples of common protists include, Chrysophytes, Dinoflagellates, Euglenoids, Slime moulds and Protozoans.

Protists and Bacteria similarities

are protists bacteria
Image showing protists classification from Wikipedia
  • The bacteria and the protists both contain cell membranes which are made up of phospholipids.
  • The structure of phospholipid is same in both bacterium and protists with a polar head and a non-polar tail.
  • Glycolysis, which is a process for glucose metabolism is common in both bacteria and protists
  • The DNA replication process is quite similar in both with minor differences.
  • The genetic code is similar in both multicellular bacteria and unicellular protists.
  • The most basic processes to sustain life of a living cell, Transcription and translation are also common in both protists and bacteria.
  • Both types of organism require energy and nutrients to maintain their lives and a continuous growth.

Protists vs Bacteria

Their cell size is very large.Cells are very small in size.
They contain a well-functioning Nucleus.They have no Nucleus at all.
They have a well-defined membrane bound organelles, such as endoplasmic reticulum, Golgi apparatus, mitochondria etc.They do not contain any membrane bound organelles.
A majority of protists species are unicellular.In bacteria, all species are unicellular.
Protists come under eukaryotes.Bacteria fall under prokaryotes.
Their genetic material is present inside the nucleoid.In bacteria nucleus contains the genetic material.
They belong to Protists kingdom.They belong to Monera kingdom.
They are found primarily in aquatic regions.They are ubiquitously present.
The mode of nutrition is autotrophic and heterotrophic. Autotrophs use photosynthesis and chemosynthesis for food.Here, the autotrophs derive their food using photosynthesis.
They follow asexual mode of reproduction by fission or DNA transfer, which is primitive sexual reproduction.They follow asexual and sexual mode of reproduction using cell fusion and zygote formation.
Protists have been classified as protozoans, Dinoflagellates, Euglenoids, slime moulds and Chrysophytes.Bacteria has been classified as Archaebacteria and Eubacteria.
Difference between Protists and Bacteria

Structure of Protists vs Bacteria

In protists such as algae cell wall is made up of cellulose, in fungi it is made of chitin.The bacterial cell wall is mostly formed of peptidoglycans.
Protists contain well-defined organelles.They do not have any well-defined organelles
They are complex and more evolved organisms.They are much simpler and comparatively less evolved.
Structure differences between protists and bacteria

Are protists bigger than Bacteria?

Yes, some protists are bigger than bacteria. Diverse organisms are kept in a single kingdom protist and out of all algae are largest in size than bacteria which are less than 1mm in size. Protists vary in their size; the common range is 5µm to 3mm.

Why are Protists not classified as Bacteria?

Protists are not classified as Bacteria in the same group because protists contain complex cells. Bacteria and most of the protists are unicellular organisms. The main difference lies in the cell type they possess, bacteria contain a prokaryotic cell and has been placed in Monera kingdom, on the other hand protists contain a eukaryotic cell.

The kingdom protist is difficult to characterize because of its diversity. The organisms that fall under this kingdom shows variation in their cell structure, mode of nutrition and reproduction.

Do Protists eat Bacteria?

Yes, protists do prey on bacteria. They swallow their food by the process called Endocytosis, that is initiated from the cell membrane. They wrap around the bacteria and creates a food vacuole around the bacteria. Toxins are released in this vacuole which seems to be a food storage compartment to hydrolyze the food and then digested food is passed into the cytoplasm.


Concluding the article we can say that “protists” and “bacteria” have many differences than similarities, that is one of the reason to separate the class of these two organisms.

Sneha Sah

Hey! I am Sneha Sah, I have completed post graduation in Biotechnology. Science has always been fascinating to me and writing is my passion. As an academic writer my aim is to make Science easy and simple to learn and read. Reach me at-

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