Cellular Biology III

Question 1

Name 5 drugs that act on microtubules and the clincal indication for which they are used.

Answer 1

1.) Mebendazole/thiabendazole (antihelminthic); 2.) Griseofulvin (antifungal); 3.) Vincristine/vinblastine (anti-cancer); 4.) Paclitaxel (anti breast-cancer); 5.) Colchicine (anti-gout) (p.76)

Question 2

Describe the mutation associated with Chédiak- Higashi Syndrome.

Answer 2

Mutation in the lysosomal trafficking regulator gene (LYST) whose product is required for the microtubule-dependent sorting of endosomal proteins into late multivesicular endosomes (p.76)

Question 3

What are the clinical manifestations of Chédiak- Higashi Syndrome?

Answer 3

Recurrent pyogenic infections, partial albinism, peripheral neuropathy (p. 76)

Question 4

Describe the structure of cilia.

Answer 4

9+2 arrangement of microtubules with axonemal dyenin ATPase arms that link peripheral 9 doublets and cause bending of cilium by differential sliding of doublets (p.76)

Question 5

What is the pathology associated with Kartagener’s syndrome (primary ciliary dyskinesia)?

Answer 5

Immotile cilia due to a dynein arm defect (p.76)

Question 6

What are the clinical manifestations of Kartagener’s syndrome?

Answer 6

Male inferfility (immotile sperm); decreased female fertility, bronchiectasis, recurrent sinusitis (bacteria and particles not pushed out); associated with situs inversus (p.76)

Question 7

Name the three classes of cytoskeletal elements.

Answer 7

1.) Actin and Myosin; 2.) Microtubules; 3.) Intermediate filaments (p.76)

Question 8

Name four places where Actin and Myosin filaments are found.

Answer 8

Microvilli, muscle contraction, cytokinesis, adherens junctions (p.76)

Question 9

Name the principle function of microtubules and 5 places where they can be found.

Answer 9

Function: movement; cilia, flagella, mitotic spindle, axonal trafficking, centrioles (p.76)

Question 10

Name the principle function of intermediate filaments and 6 places where they can be found.

Answer 10

Function: structure; Vimentin, desmin, cytokeratin, lamins, GFAP, neurofilaments (p.76)

Question 11

Describe the contents of a plasma membrane.

Answer 11

An asymmetric lipid bilayer containing cholesterol, phospholipids, sphingolipids, glycolipids, and proteins (p.76)

Question 12

What is the immunohistochemical stain for connective tissue?

Answer 12

Vimentin (p.76)

Question 13

What is the immunohistochemical stain for muscle?

Answer 13

Desmin (p.76)

Question 14

What is the immunohistochemical stain for Epithelial Cells?

Answer 14

Cytokeratin (p.76)

Question 15

What is the immunohistochemical stain for Neuorglia?

Answer 15

GFAP (p.76)

Question 16

What is the immunohistochemical stain for neurons?

Answer 16

Neurofilaments (p.76)

Question 17

Describe the location and mechanism of action of the sodium-potassium pump.

Answer 17

Na+/K+/ATPase is located in the plasma membrane with the ATP site on the cystolic side. For each ATP consumed, 3Na+ go out and 2K+ enter the cell. During the cycle, the pump is phosphorylated (p.77)

Question 18

What does Ouabain do?

Answer 18

Inhibits the sodium-potassium pump by binding to the K+ site (p.77)

Question 19

What is the mechanism of action of Cardiac Glycosides?

Answer 19

Direct inhibition of the Na+/K+/ATPase, leading to indirect inhibition of the Na+/Ca2+ exchange. This increases intracellular calcium and cardiac contractility (p.77)

Question 20

Name two Cardiac Glycosides.

Answer 20

Digitoxin, Digoxin

Question 21

What is the primary function of collagen?

Answer 21

Organization and strengthening of the extracellular matrix. It is the most abundant protein in the body and is extensively modified by posttranslational modification (p.77)

Question 22

Where is Type I Collagen found?

Answer 22

Bone, skin, tendon, dentin, fascia, cornea, late wound repair. Most abundant type (90%)

Question 23

What condition is associated with defective type I collagen?

Answer 23

Osteogenesis Imperfecta (p.77)