Cytoskeleton — Structure & Function

How Do Cells Keep Their Shape?

Microfilaments, intermediate filaments, and microtubules form the cytoskeleton.

This structure helps cells keep their shape and it also helps with anchorage and movement (like in muscle cells). This is a massive benefit for animal cells because they don't have the rigid cell wall that plant cells have, which makes them more fragile. In other cells, cilia and flagella, the little tails that help them move around, are also considered to be part of the cytoskeleton.

Try to remember that this structure is quite literally the skeleton of the cell. It's even in the name. Cyto means cell and skeleton means, well, skeleton.

Microtubules are polymers of tubulin proteins and are the largest cytoskeletal fibers. Microfilaments are polymers of actin proteins and are a very important structure for cell movement. Intermediate filaments have a very diverse makeup. They create a more permanent structure which is essential for cell shape and support.

$$\color{#8925ae}{\text{Vocabulary Review:}}$$

$\color{#8925ae}{\text{Vacuole}}$ : Organelle that contains water and nutrients. Refrigerator of the cell

$\color{#8925ae}{\text{Golgi Apparatus}}$ : The Golgi Apparatus stores, sorts, and modifies proteins and lipids. Post office of the cell

$\color{#8925ae}{\text{Cytoskeleton}}$ : Helps the cell maintain its shape and assists with movement. Skeleton of the cell

$\color{#8925ae}{\text{Mitochondria}}$ : Mitochondria make ATP (energy). Powerhouse of the cell

$\color{#8925ae}{\text{Ribosome}}$ : Ribosomes create polypeptide chains and proteins. Factory of the cell

$\color{#8925ae}{\text{Endoplasmic Reticulum}}$ : The smooth ER makes lipids for the cellular membrane. The rough ER assembles proteins and transports them into and out of the cell

$\color{#8925ae}{\text{Nucleus}}$ : The nucleus contains the genetic material, DNA, of the cell. Brain of the cell

Cellular Structure

A cell's cytoskeleton forms its internal framework, giving it structure and support.

Think of the job your own skeleton does: It holds you up, gives you shape, and helps you move. Cyto means "cell", so a cytoskeleton is just the cell's skeleton, and it does those same jobs.

However, it is not made of bones. It is made of long, stretchy proteins. There are three main types of fibers that make up its structure: microfilaments, intermediate filaments, and microtubules. The fibers are able to rapidly assemble and disassemble to fit the needs of the cell.

In addition to helping a cell keep its shape, the cytoskeleton is also attached to most organelles. This helps keep the organelles in place and assists with the transport of various molecules throughout the cell.

Aside from support, it also helps with cell motility. This is particularly true of cells that use pseudopods (literally "fake feet") to drag themselves along. Other cells have little tails called cilia and flagella that help them move around. These are also considered to be a part of the cytoskeleton.

What Does the Cytoskeleton Do?

The cytoskeleton helps maintain the shape and structure of the cell as well as provides a means for transport. For example, let's look at a specific type of cell called a neuron:

How does it maintain the shape of its long projecting axon? How does a protein made in the cell body (the soma) get to the axon terminals where it will be used? Well, it's all with the help of the cytoskeleton.

This structure is literally the cell's (cyto) skeleton (skeleton). It helps the cell keep its shape, especially in cells without the support of a cell wall. It also acts as a kind of highway system for transporting things around the cell.

It has three major components:

• Actin
• Microtubules
• Intermediate filaments

All of these major components have their own properties and functions in the cell. For example, the protein actin has the ability to grow and shrink rapidly, and is therefore often used by a cell to extend and retract its plasma membrane to move around. Microtubules are more stable and are often used for cellular shipment of products. Finally, intermediate filaments are the most stable and are often used to maintain a cell's structure. Take a look at the protein filaments in the image below.

(Video) Cells - Cytoskeleton

by Mahalo

The cytoskeleton is found in both eukaryotic cells and prokaryotic cells and is essentially a network of fibers. Specifically, it consists of microfilaments, microtubules, and intermediate filaments.

Its function is to maintain the cell's shape and provide some structural rigidity. This is especially important in animal cells, which don't have the tough cell wall that plant cells have. In addition, it helps the cell move, helps the different components of the cell move around, and assists with separating daughter cells during cytokinesis.