Plant Cell Wall: Function, Structure & Composition

  • 0:02 What Is a Cell Wall?
  • 0:32 Function of a Cell Wall
  • 2:46 Structure & Composition
  • 4:22 Lesson Summary
Create An Account
To Start This Course Today
Used by over 10 million students worldwide
Create An Account
Try it free for 5 days
Lesson Transcript
Instructor: Kelly Robson

Kelly has taught High School Science and Applied Communications. She holds an Education Specialist Degree in Ed. Leadership.

All cells have a cell membrane on the outside of them that acts like a skin. Plant cells go one step further and have a cell wall - a protective outside that provides support and other functions.

What Is a Cell Wall?

All living things are composed of cells. They are the building blocks of all life. Cells come in many different shapes and have different functions. Plant and animal cells are different, too. The main difference between plant and animal cells is that plant cells have a cell wall on the outer layer, whereas animal cells only have a cell membrane. The cell wall is a protective layer outside the cell membrane that also provides support for the cell's structure.

Function of a Cell Wall

The cell wall gives the plant its actual shape. It acts as a gatekeeper, because it determines what can come in and out of the cell in order to keep the cell protected. It is kind of like the outside bricks of a castle, only, as you will learn as you read on, there are holes throughout this castle. Those holes do make the cell vulnerable, but they are important to the function of the cell.

A plant cell has a cell wall, whereas an animal cell only has a cell membrane.
Plant Cell

A redwood tree and a dandelion both have cell walls on the outside of all of their cells. The cell walls are there to give the plants their shape and support; however, the cell walls act and are constructed a little different to meet the needs of the particular plant. For instance, a 100-foot redwood tree needs a very strong and rigid plant cell wall so that it can grow to its great height and not fall over in the wind. On the other hand, a little yellow dandelion out in the field needs to have more plasticity so that it can bend, not break, as the wind blows through the field.

A dandelion needs to have plasticity to be able to bend in the wind.
Dandelion

Have you ever forgotten to water the flowers? They may not be able to talk, but they will let you know when they're thirsty, as they begin to droop over. Their shape is still being maintained by the cell wall so that, as soon as you water the plant, it can pick itself back up again. On the other hand, if you water too much, the cell wall also makes sure that the cell does not burst. It protects the cell from overexpansion.

The cell wall protects the plant and cells from the many insects and pathogens that could harm the plant, but the cell wall still has its vulnerable areas. There are holes all over the cell wall called plasmodesmata. These are holes that allow for nutrients to enter the cell as well as waste to exit the cell. These small holes can cause the cell to lose water, and this is when the plant will start to droop. But as soon as the plant can get a drink, it will bounce right back up to its proper shape.

Here is a list of the basic plant cell wall functions:

  • Provide support and limited plasticity
  • Prevent loss of water
  • Protection from insects and pathogens
  • Filter
  • Prevent overexpansion caused by too much water
  • Keep the shape of the plant
  • Allow plants to grow to great heights

Structure and Composition

The plant cell wall is composed of cellulose. Cellulose is a structural carbohydrate and is considered a complex sugar because it is used in both protection and structure. The plant cell wall consists of three layers. Each layer has its own unique structure and function. The layers may vary depending on the type of plant and its needs.

Cell walls are composed of three layers.
Cell Wall Layers

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

Unlock Your Education

See for yourself why 10 million people use Study.com

Become a Study.com member and start learning now.
Become a Member

Already a member? Log In

Earning College Credit

Did you know… We have over 100 college courses that prepare you to earn credit by exam that is accepted by over 2,900 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? Study.com 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.

1
You just finished your first lesson. Study.com has thousands of lessons to help you meet your educational goals.
5
You're making great progress. Keep it up!
10
Congrats on viewing 10 lessons! You're doing great.
Keep clicking that 'next lesson' button whenever you finish a lesson and its quiz. Got It
You now have full access to our lessons and courses. Watch the lesson now or keep exploring. Got It
You're 25% of the way through this course! Keep going at this rate and you'll be done before you know it.
Two days in a row, nice! Keep your streak going to get the most of your learning and reach your goal faster.