1. Describe the two phenomena that give rise to the diversity of adhesion molecules such as cadherins. What additional phenomenon gives rise to the diversity of integrins?

2. Cadherins are known to mediate homophilic interactions between cells. What is a homophilic interaction, and how can it be demonstrated experimentally for E-cadherins? What component of the extracellular environment is required for the homophilic interactions mediated by cadherins, and how can this requirement be demonstrated?

3. Together with their role in connecting the lateral membranes of adjacent epithelial cells, adherens junctions play a role in controlling cell shape. What associated intracellular structure and proteins are involved in this role?

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4. What is the normal function of tight junctions? What can happen to tissues when tight junctions do not function properly?

5. Gap junctions between cardiac muscle cells and gap junctions between uterine smooth muscle cells form connections that provide for rapid communication. What is this phenomenon called? How is communication among uterine smooth muscle cells up-regulated for parturition (childbirth)?

6. What is collagen, and how is it synthesized? How do we know that collagen is required for tissue integrity?

7. Explain how changes in integrin structure mediate outside-in and inside-out signaling.

8. Compare the functions and properties of each of three types of macromolecules that are abundant in the ECM of all tissues.

9. Many proteoglycans have signaling roles. Regulation of feeding behavior by syndecans in the hypothalamic region of the brain is one example. How is this regulation accomplished?

10. You have synthesized an oligopeptide containing an RGD motif surrounded by other amino acids. What is the effect of this peptide when added to a fibroblast cell culture grown on a layer of fibronectin adsorbed to the tissue culture dish? Why does this happen?

11. Describe the major activity and possible localization of the three major subgroups of proteins that remodel or degrade the ECM in physiological or pathological tissue remodeling. Identify a pathological condition in which these proteins play a key role.

12. Blood clotting is a crucial function for mammalian survival. How do the multi-adhesive properties of fibronectin lead to the recruitment of platelets to blood clots?

13. How do changes in molecular connections between the ECM and the cytoskeleton give rise to Duchenne muscular dystrophy?

14. To fight infection, leukocytes move rapidly from the blood into sites of infection in the tissues. What is this process called? How are adhesion molecules involved in this process?

15. The structure of a plant cell wall needs to loosen to accommodate cell growth. What signaling molecule controls this process?

16. Compare plasmodesmata in plant cells with gap junctions and tunneling nanotubes in animal cells.