Exam 4 (5)

Question 1

Animal Cell Organization

Answer 1

Tissues!! Means they are able to interact with one another and the extracellular environment (meshwork of secreted proteins and polysaccharides) –> bidirectional transfer of information possible

Question 2

Cell-Cell Adhesion Connections (Class + 4 Examples)

Answer 2

[CAMS] Transmembrane Cell Adhesion Molecules (combines weak cis (same cell/structure; lateral interactions with weak trans (across cells) to form tight adhesions); a direct association of cells

1. Tight Junctions: closes the space between cells
2. Adherens Junctions: actin-filament based
3. Desmosomes: intermediate filament based
4. Gap Junctions: formation of small channels in between cells

Question 3

Cell-Matrix Adhesion Connections (Class + 2 Examples)

Answer 3

Transmembrane Adhesion Receptors; indirect association of cells (part of the ECM; every one attaches to these)

1. Focal Adhesions : actin filaments in cell anchor to ECM
2. Hemidesmosomes: intermediate filaments in cell anchor to ECM

Question 4

2 Types of Interactions between Adhering Molecules

Answer 4

Homophilic: favorable interactions with self
Heterophilic: favorable interactions with other adhering molecules or compounds in general

Question 5

Special Note with Cadherin

Answer 5

Likes to make homophilic linkages; if we put cells expressing multiple different types of adherin together, we will end up seeing sorting into multiple broad “tissues”

Question 6

Apical vs Basolateral Membrane

Answer 6

Apical: faces the free surface
Basolateral: faces the cell-cell space

Question 7

Tight Junction: Where and Purpose

Answer 7

Found running around the apical membrane in a belt-like conformation; prevents anything extracellular from passing in between cells AND plasma membrane proteins undergoing lateral diffusion to technically switch membrane spaces (apical to basolateral or vice versa)