W5 Cell Biology 3 - Julia Potter

Question 1

How do cells attach to the extracellular macromolecules in extracellular matrix?

Answer 1

Integrins - predominant adhesion molecule that binds to molecules in the matrix, including collagen fibrils, elastic fibres and glycosaminoglycans such as chondroitin sulphate.

Integrins also function to bind platelets to endothelial cells and platelets to platelets as part of coagulation.

Question 2

Give some examples of extracellular matrix.

Answer 2

Basal lamina - basement of epithelial cells
Tendons
Connective tissue sheaths

Question 3

What proteins are involved in cell to cell interactions?

Answer 3

IgCAMs and cadherins - bind to complementary molecules on adhacent cells, constructing tissues, organs.

Selectins - bind to glycoproteins (e.g. mucins) on other cell surfaces

Question 4

Provide 3 examples of cell-cell junctions in tissues and organs.

Answer 4

tight junctions - e.g. epithelium

gap junctions - e.g. ion channels that allow continuous cytoplasm between cells, important in myocardiocytes.

adherens junction and desmosomes - cadherins connect the cytoskeleton of 2 adjacent cells.