ECM and Cell Communication Flashcards
(33 cards)
what is multicellularity and why do we have it
- different cells preform different functions to contribute to the homeostasis and total function of the organismq
where is the ECM
usually on the outside of cells
what are the 3 structural components of the ECM
interstitial fluid, proteins, polysaccharides
what is interstitial fluid
solution that bathes and surrounds the cells of multicellular animals
how do proteins contribute to ECM structure
adhesive and structural components
how do polysaccharides contribute to the ECM
gel-like matrix
what are GAGS (glucosamino-glycans) and what do they do
- what do they form?
- most abundant polysaccharide in ECM
- give strength and elasticity to ECM
- negatively charged, attract positively charged ions and water which help with shock absorption
- form proteoglycans
what is glycosylation and where does it occur
happens in the ER and Golgi
- attachment of sugar to protein
- how proteoglycans in the ECM are made
what are some functions of the ECM
- strength: prevent tearing
- structural support: skeleton
- organization: cells attach to ECM and bind to body parts
- cell signalling: how multicellular organisms sense the environment
what are the adhesive proteins in ECM
fibronectin and laminin
what are the structural proteins in ECM
collagen and elastin
what is fibronectin
connects cells to the ECM and helps to organize components in the ECM
what is laminin
connects cells to the ECM and helps to organize components in the basal lamina
what is collagen and what does it provide
forms large fibres and interconnected fibrous networks in the ECM
- provides tensile strength
what is elastin and what does it provide
forms elastic fibres in the ECM that can stretch and recoil
- provides elasticity
how is collagen produced
- procollagen polypeptides are synthesized in the ER lumen and assembled into triple helix
- the procollagen is secreted from the cell and more modifications are done
- the removal of extension peptides allows collagen to assemble into fibrils
- the collagen fibrils assemble into larger collagen fibrils
how is a plant cell ECM organized?
- protective layer on the outside of the plasma membrane
- resist compression, more rigid
what is a plant ECM composed of
cellulose (absorbing molecules)
what are cell junctions and what are three examples of them
cell to cell and cell to ECM linkages
- anchoring junctions
- tight junctions
- gap junctions
function of anchoring junctions
anchor cells to one another or to the ECM
what is the function of tight junctions
seal cells together into a tissue
what is the function of gap junctions
allow cells to communicate directly with each other
what do anchoring junctions rely on?
cell adhesion molecuels (CAMs)
- cadherin and integrin
what is cadherin and what does it require
- what do linker proteins do
- creates cell junctions
- calcium to bind together (changes confirmation)
- linker proteins connect cadherins to actin or intermediate filaments in the cytosol
