ch19

Question 1

Anchoring junctions (cadherin)

Answer 1

Function: provide structural support & adhesion between adjacent cells
Significance: Mediate cell-cell adhesion
Activation: Intracellular calcium

Question 2

tight junctions

Answer 2

Function: Form a barrier to prevent leakage
Role: Critical in maintaining tissue integrity & selectively controlling paracellular transport

Question 3

Channel gap junctions (connexins and connexons)

Answer 3

Function: Facilitate direct communication & exchange of small molecules between neighboring cells
Structure: 6 connexins=1 connexon
Regulation: Connexons open and close with changes in calcium levels, playing a role in cellular communication

Question 4

calcium role in gap junction

Answer 4

calcium binding to connexin molecules leads to closing of gap junctions

Question 5

calcium role in anchoring junctions

Answer 5

prevent it from flexing

Question 5

collagen as a prominent component

Answer 5

Function: Provide structure and flexibility
Significance: Most abundant protein

Question 6

categories of ECM components

Answer 6

-proteoglycans and GAGs

-fibrous proteins

-glycoproteins

Question 7

Fibrillar collagen

Answer 7

-Type I, II, III

-triple helix, 1000 amino chains

-glycines on inside

-undergo post-translational modification

Question 8

collagen in basal lamina

Answer 8

-Type IV

-three alpha chains

-intertwined with laminin

-stabilized by entactin/nidogen binding

Question 9

Story of collagen synthesis (Synthesis & modification/secretion/assembly)

Answer 9

-Begins in ER with formation of procollagen
-Post-translational modifications
-Secretion to extracellular space
-Assembly into function collagen fibrils

Question 10

ECM significance

Answer 10

serves as a physical barrier, an anchorage site, or a movement track for cell migration, also controlling fundamental behaviors