L5 Regulations of animal cell shape

three major components of the cytoskeleton?

Microfilaments, intermediate filaments, and microtubules.

microfilaments structure and function?

Thin strands like aho, composed of actin; provide structural support and enable cell movement. Resists tension.

intermediate filaments structure and function

If microfilaments is aho, this is miro. Composed of keratin coiled together. Super strong and tightly coiled. Maintains cell shape and anchors organelles.

microtubules structure and function

hollow tubes composed of tubulin; they resist compression, movement and organelle movement (walking motor proteins), and maintaining cell shape.

role of the cytoskeleton in regulating cell shape

maintains structural integrity and allows for changes in shape necessary for cell movement and division.

three main types of cell junctions

Tight, desmosome, and gap.

tight junctions structure and function

Like the “water seal” of the junctions. Prevents movement of fluids across cells layers. Not good at forcing cells to stay together.

desmosome junctions structure and function

Like the “zip” of the junctions. Adhere cells together through intermediate filaments. Prevent cells from being pulled apart.

gap junctions structure and function

Like the “tunnel” of the junctions. Allow ions and small molecules to pass between cells. Allows rapid intercellular comms.

What is the ECM made of?

composed of material secreted by the cell. eg, proteins, glycoproteins (like collagen), and polysaccharides.

Proteoglycan

Proteins with A LOT of sugar. They trap water; water resists compression; and therefore helps retain tissue shape.

Fibronectins & Integrins

(the dinosaur looking thing) attach cells to ECM, (membrane proteins) attach ECM to cytoskeleton. Together they provide a communication link between the cell interior and the ECM.