ch. 20 cell bio

forms multimers of single polypeptide chains, initially coiled as a triple helix.

• provides strong linkages in ECM
• fibronectin
• integrins

dimeric protein connected at c terminal end by dual disulphide linkages

• integral membrane proteins
• extracellularly (ECM)
• intracellularly (cytoskeleton)
• humans have 24 types of integrins

• complex, branched polysaccharides
• prototypical GAG=hyaluronan

fill remainder of ECM and consists of various proteins linked to GAGs

seal between cells formed by occludin and claudin

joins an actin bundle in one cell to adjacent cell. Cadherins

join intermediate filaments (keratin filaments) bound intracellularly. Cadherins

integrins bridge link between anchor protein and basal lamina. and keratin filaments still associate with cytoplasmic plaque like desmosomes

channel for cell to cell transfer of small analytes. provided by hexamer units called connexons

• cellulose microfibrils (analagous to collagen) 
• crosslinking protein is pectin and glycan
• plant cells are connected through plasmodesmata

• also called pluripotential cells
• obtained from early embryos in blastocyst stage

• 1) right signals
• 2) environmental cues
• 3) right time during development

• activated phosphate signals for cell proliferation which leads to cancer
• oncogenic kinase can be blocked with a drug and doesn't send out signal so no cancer