What is Mitosis? - Definition, Stages & Function

An error occurred trying to load this video.

Try refreshing the page, or contact customer support.

Coming up next: What is Meiosis? - Steps & Results

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

Take Quiz Watch Next Lesson
Your next lesson will play in 10 seconds
  • 0:02 Mitosis
  • 1:24 Interphase
  • 2:49 Stages
  • 5:04 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: Rebecca Gillaspy

Dr. Gillaspy has taught health science at University of Phoenix and Ashford University and has a degree from Palmer College of Chiropractic.

Every day your body cells are dividing using a process called mitosis. This allows you to grow and replace damaged or worn out cells. Learn about the stages of mitosis: prophase, metaphase, anaphase and telophase.


From the day you enter kindergarten to the day you enter middle school, your body goes through a lot of changes. One thing that's pretty obvious during this stage of your life is how much bigger you get. I bet you never thought about it, but the fact that you're bigger means that you have more cells. Your body continually makes new cells by dividing the ones that already exist. So, all of the body cells you had when you were a kindergartener divided a bunch of times and little you became big you. This process of dividing body cells and their nuclei is called mitosis. Let's take a look at how this process works.

We already learned that mitosis is a type of cell division that produces more cells. This not only helps you grow, but also repairs damage when you do things like fall off your bike and scrape the skin from your knee. Any time your body needs to grow or repair, mitosis begins. The result is more of the exact same cells. So when you damage your skin cells, mitosis gives you more skin cells. When your liver needs to get bigger because you grew, your liver cells divide using mitosis to make more liver cells. Making identical cells is a good thing. After all, who wants a liver cell growing on their skin?


Your cells divide at different rates. For example, when you are grown, your liver cells lose interest in mitosis and only do it when they really need to. Your skin cells, on the other hand, never seem to lose the thrill of division. It seems as if your skin cells are always dividing by mitosis to renew and repair your skin. But even though your skin cells divide a lot, they are not dividing all of the time. That's a good thing, because just think about the consequences of non-stop mitosis. You would continue to grow with no end in sight!

Most of the time your body cells are in what we call interphase, which is a phase of a cell's life in which the cell is growing, replicating DNA and carrying out general activities. So, your cells spend most of their time preparing for that big moment when they can finally divide, just like you spend most of your time learning in school to prepare for your big graduation moment. You might want to think of interphase as the in-between phase because it's in between periods of mitosis. Of course, this doesn't mean interphase is not important. It's during interphase that the DNA inside the nucleus of your cells gets replicated or copied. You might remember that your DNA contains your genetic information. So if you are making new cells, you certainly want to pass that DNA along.


When all of the DNA has been copied, your cell is ready to head into the stages of mitosis. A good way to keep them straight and learn the order in which they occur is to remember PMAT. That stands for the four stages: prophase, metaphase, anaphase and telophase. It's in prophase that we start to see chromosomes. The DNA that was duplicated earlier changes and kind of organizes and condenses into chromosomes that are now visible. These chromosomes are inside the nucleus, but the nucleus breaks down during prophase, so it will be going away as we move through mitosis. This is the first step, so it might help you to think about the prefix 'pro-' as meaning before, kind of like the 'prologue' of a book is that thing that comes before the story begins.

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