Bacteria vs. Protists

An error occurred trying to load this video.

Try refreshing the page, or contact customer support.

Coming up next: Autotrophic Protists: Definition, Characteristics & Examples

You're on a roll. Keep up the good work!

Take Quiz Watch Next Lesson
Your next lesson will play in 10 seconds
  • 0:01 Introduction to…
  • 0:37 Characteristics of Bacteria
  • 2:01 Characteristics of Protists
  • 3:47 The Major Differences
  • 4:13 The Similarities
  • 4:36 Lesson Summary
Save Save Save

Want to watch this again later?

Log in or sign up to add this lesson to a Custom Course.

Log in or Sign up

Speed Speed

Recommended Lessons and Courses for You

Lesson Transcript
Instructor: Danielle Haak

Danielle has a PhD in Natural Resource Sciences and a MSc in Biological Sciences

There can be a lot of confusion when it comes to differentiating among small organisms like bacteria and protists. This lesson will help you see how they differ and give examples of each!

Introduction to Bacteria & Protists

The world has more organisms than scientists have been able to count and classify. Identification can be tricky because so many organisms are microscopic in size and invisible to the naked eye. Two of the categories that often get confused with one another are bacteria, which are single-celled microbes, and protists, which are eukaryotic organisms that are not plants, fungi, or animals. Let's take a look at what makes each of these organisms unique more than just these simple definitions, and while we're at it, we can also see how they are similar.

Characteristics of Bacteria

What are bacteria? They are some of the oldest known organisms and are classified as prokaryotes. What does that mean? Well, prokaryotes are simple, single-celled organisms that lack organelles. If we look at bacteria, we see a single-celled organism with a flexible cell wall, a semi-permeable cell membrane, single-loop DNA, and enzymes. There are no internal compartments or structures, and no sexual reproduction takes place.

When bacteria multiply, it's usually through the process of asexual reproduction by binary fission. We may see colonies or groups of bacteria form, but each individual bacterium in that group is still a unicellular organism. Bacteria have three primary shapes: cocci (ball-shaped), bacilli (rod-shaped), and spirilla (spiral-shaped). Their differences are generally biochemical in nature, rather than physical. Some bacteria are helpful to humans, while others are harmful.

One type of bacteria you may be unknowingly familiar with is Staphylococcus aureus. These bacteria can cause digestive problems when consumed on contaminated food. The results are generally referred to as food poisoning. They're also the culprit of staph infections, which can be mild, like a pimple, or severe, like meningitis!

Characteristics of Protists

Now let's look at the group of organisms known as protists. These are small eukaryotes. A eukaroytic organism can be unicellular or multicellular; most (but not all) protists are actually unicellular. Unlike bacteria, protists have specialized organelles, including a true nucleus confined by a nuclear membrane. This compartmentalization differentiates protists from bacteria. You can think of prokaryotes (bacteria) that have no nucleus or organelles like an empty house, whereas eukaryotes (protists) are like a house full of appliances that have different functions. Both are still houses, one is just more complex than the other.

Additionally, protists are generally larger in size. Some protists ingest food, while others may make their own food. These photosynthetic protists, such as blue-green algae, contain chloroplasts, too. We can further classify protists based on their functions. There are animal-like protists (heterotrophs), fungal-like protists (decomposers), and plant-like protists (photosynthetic).

To unlock this lesson you must be a Member.
Create your account

Register to view this lesson

Are you a student or a teacher?

Unlock Your Education

See for yourself why 30 million people use

Become a member and start learning now.
Become a Member  Back
What teachers are saying about
Try it risk-free for 30 days

Earning College Credit

Did you know… We have over 200 college courses that prepare you to earn credit by exam that is accepted by over 1,500 colleges and universities. You can test out of the first two years of college and save thousands off your degree. Anyone can earn credit-by-exam regardless of age or education level.

To learn more, visit our Earning Credit Page

Transferring credit to the school of your choice

Not sure what college you want to attend yet? has thousands of articles about every imaginable degree, area of study and career path that can help you find the school that's right for you.

Create an account to start this course today
Try it risk-free for 30 days!
Create an account