CELS191 LECTURE 5 - Cytoskeleton and Cell Junctions

Flashcards covering key concepts related to the cytoskeleton, its components, and cell junctions.

Cytoskeleton

A network of protein filaments and tubules that helps maintain cell shape and position of organelles.

Microtubules

Components of the cytoskeleton composed of tubulin subunits that resist compression and assist in maintaining cell shape.

Actin

A protein that forms microfilaments, which support cell shape and facilitate movement.

Intermediate Filaments

Fibrous proteins that provide structural support and stability to cells - anchoring organelles. They are supercoiled into “cables.”

Cilia

Hair-like structures that help in cell motility through a rowing-like motion.

Flagella

Tail-like structures that enable cell motility through a snake-like motion.

Tight Junctions

Cell junctions that hold neighboring cells tightly together to prevent fluid movement across cell layers.

Desmosomes

Anchoring junctions that provide attachments between sheets of cells, acting like rivets.

Gap Junctions

Points of cytoplasmic contact allowing ions and small molecules to pass between cells, facilitating rapid communication.

Extracellular Matrix (ECM)

A complex network of proteins and carbohydrates (glycoproteins) secreted by cells that provides structural and biochemical support. These link together to resist compression, trap water, and maintain shape.

Collagen

The most abundant glycoprotein in the ECM, known for its tensile strength.

Proteoglycans

Proteins with extensive sugar additions that trap water within the ECM and help maintain tissue shape.

Fibronectins

Glycoproteins that attach cells to the ECM.

Integrins

Membrane proteins that connect the ECM to the cytoskeleton, facilitating communication between the ECM and the cell.

Intermediate Filaments Composition

• Keratins in hair.

• Lamins in the nucleus.

• Neurofilaments in neurons.

Microfilaments

Interactions between actin and motor proteins such as myosin support cell movement. Help to resist tension.

Extracellular Matrix (ECM) Composition

Collagen, fibronectins (attach cells to ECM physically), Integrins allow ECM and cytoskeleton to communicate.