Lecture 6 - Extracellular Structures Flashcards
What is the structure and function of a plant cell wall?
structure: cellulose (polysaccharide)
function: maintains cell shape and prevents excess uptake of water
What is the function of an animal extracellular matrix? (ECM)
- maintains cell attachments across long distances
- allows communication
- maintains tissue integrity
- stores growth factors
Describe the different parts of the ECM structure… five components!!
- secreted glycoproteins = proteins covalently linked to sugars
- collagen = forms structure of ECM
- integrins = integral membrane proteins that link the ECM to the CSK
- fibronectin = links collagen fibers to integrins
- proteogylcans = hydrate tissues
What is an example of an animal ECM?
epithelial layers
What is a tumor?
mass of cells that arose from unregulated cell division
Why are epithelial cells vulnerable to cancer?
they are exposed to carcinogens in the environment
What is the major step in cancer progression?
detachment from the ECM
What are animal cell-cell attachments?
- happen over long distances, cells can be directly attached to one another by three different attachment styles
- set of intercellular junctions in epithelial layers
- moves from apical to basal
What are tight junctions?
- function as rivets to seal cells together
- prevents the passage of molecules between cells and the environment ( and vice versa)
What are desmosomes?
- distribute stretching forces across a tissue
- connect adjacent cytoskeleton via intermediate filaments
What are gap functions?
- provide non-selective transport of small molecules between adjacent cells
- large channels allow sharing of nutrients and signals
- allows coordination of muscle contraction in cardiac muscle
- calcium can spread between cells and is the contractile signal
