Tissue Architecture

Question 1

Cytoskeletal filaments (3)

Answer 1

Intermediate filiments
Microtubules
Microfilaments

Question 2

Intermediate Filaments (4)

Answer 2

1. Great tensile strength due to rope-like structure.
2. Found in cytoplasm of most animal cells.
3. Often anchored to PM at cell-cell junctions.
4. Form mesh-like structure called nuclear lamina.

Question 3

Nuclear lamina

Answer 3

Underlies and strengthens nuclear envelope.

Question 4

Types of intermediate filiments (3 cytoplasmic and 1 nuclear)

Answer 4

Cytoplasmic
1. Keratin filiments (epithelium)
2. Vimentin and vimenten-related filiments (CT)
3. Neurofiliments (nerve cells)
Nuclear
1. Nuclear lamina (in all animal cells)

Question 5

Microtubules (5)

Answer 5

Organization

1. Long and stiff hollow tubes.
2. Rapid assembly and disassembly.
3. Extend from centrosome to cell periphery.
4. Form mitotic spindle for chromosome segregation.
5. Part of cilia and flagella.

Question 6

Taxol

Answer 6

Drug that binds and stabilizes microtubules.

Question 7

Colchicine and Vinblastine

Answer 7

Drugs that bind tubulin dimer and prevent polymerization.

Question 8

Microfilaments (3)

Answer 8

Cell movement

1. Actin filiments.
2. Present in all cells.
3. Many are unstable.

Question 9

Phalloidin

Answer 9

Drug that binds and stabilizes actin filaments.

Question 10

Cytochalasin

Answer 10

Caps filament plus ends, preventing polymerization of filaments.

Question 11

Latrunculin

Answer 11

Binds actin monomers and prevents their polymerization.

Question 12

Collagen

Answer 12

Main structural protein in ECM, connective tissue and basal laminae. Associate as fibers, sheets or transmembrane structures.

Question 13

Scurvy

Answer 13

Loss of Vit C (cofactor in collagen synthesis). Leads to wound opening, loss of teeth, sunken eyes, pal skin.

Question 14

Ehlers-Danlos Syndrome

Answer 14

Caused by mutation in collagen or collagen synthesis genes. Weakens connective tissue in sin, bones, blood vessels and organs.

Question 15

Cell Adhesion Molecule (CAM) domains (3)

Answer 15

1. Extracellular: binding to adjacent cell/matrix proteins.
2. Transmembrane: links CAM to membrane.
3. Cytoplasmic: Bind to cytoskeleton via linker proteins.

Question 16

4 Families of CAMs

Answer 16

1. Cadherins
2. Ig superfamily
3. Integrins
4. Selectins

Question 17

Cadherin superfamily and types (4)

Answer 17

Ca 2+ dependent adhesion molecule that interact with actin.
E-cadherin: epithelial.
N-cadherin: neural.
VE-cadherin: vascular-endothelial.
LI-cadherin: liver-intestine.

Question 18

Epithelia to Mesenchymal Transition (EMT)

Answer 18

Drop in E-cadherin and increase in N-cadherin. As EMT progresses, there is increased invasiveness of tumor cells and increase in metastatic potential. This is due to an increased level of imgratory capacity, invasiveness, and resistance to apoptosis.

Question 19

Ig superfamily

Answer 19

Ca 2+ independent and facilitate immune cell intercactions. Involved in recognition, binding or adhesion processes of cells.

Question 20

Selectins

Answer 20

Ca + dependent glycoprotein that binds to extracellular carbohydrates. Play a role in host defense mechanisms.

Question 21

Integrins

Answer 21

Couple the ECM to cell cytoskeleton. Can activate signaling pathways and cell-cell interactions via beta2 family.