Molecular biochem and genetics

Question 1

Dynein vs. kinesin

Answer 1

motor proteins. dynein goes retrograde to the micgrotubule (away from the direction it is being built); kinesin goes anterograde to the microtubule

Question 2

Kartagener syndrome

Answer 2

primary ciliary dyskinesia. an immotile cilia d/t a dynein (retrograde wrt the microtubule) arm defect. bronchiectasis, recurrent sinusitis, situs inversus, infertility

Question 3

What drugs affect the microtubules?

Answer 3

(microtubles get constructed very poorly):

mebendazole, griseofulvan (anti-fungal), colchicine, vincristine/vinblastine, paclitaxel (anti-CA)

Question 4

What does vimentin stain for?

Answer 4

connective tissue

Question 5

What does desmin stain for?

Answer 5

muscle

Question 6

What does cytokeratin stain for?

Answer 6

epithelial cells

Question 7

Sodium potassium pump and cxn to pharm

Answer 7

maintains the normal electrochemical gradient. pumps 3 Na out and brings 2 K in. costs 1 ATP. Digoxin works by reducing the function of the Na/K/ATPase. Recall that, in heart cells, the Na/K/ATPase pump is tied to a Na/Ca exchanger. The Na/Ca exchanger moves an Na in (along its gradient) and a Ca out. When the electrochemical gradient isn’t as well established, the Ca will stay in the heart cell longer, thus increasing contractility.

Question 8

What diseases are associated with types I, III, and IV cartilage?

Answer 8

I: osteogenesis imperfecta
III: vascular Ehlers-Danlos syndrome
IV: target of goodpasteurs, defective in Alport syndrome (kidney disease, hearing loss, and eye problems, usually inherited in an X-linked fashion but may be autosomal recessive)

Question 9

Steps to collagen synthesis; diseases that affect each step

Answer 9

synthesis, hydroxylation (vitamin C deficiency), glycosylation (important for formation of a procollagen and a triple helix. If you can’t form the triple helix, you have osteogenesis imperfect) (all in the RER), then exocytosis. outside of fibroblasts, there is proteolytic processing and cross-linking (Copper deficiency, Ehlers-Danlos)

Question 10

Osteogenesis imperfecta manifestations

Answer 10

blue sclera, hearing loss from abnormal ossicles, dental imperfections, lots of fractures. usually autosomal dominant, often from decr. production of type I collagen

Question 11

Symptoms of Ehler’s danlos syndrome

Answer 11

easy bruisng, hypermobile joints, joint dislocation, berry aneurysms, and organ rupture.
many types, all due to problems with collagen cross linking

Question 12

Classic Ehler’s Dnalos vs. vascular Ehler’s danlos

Answer 12

classic: joint and skin symptoms d/t type V collagen mutation. vascular: vascular symptoms and organ rupture d/t defects with type III collagen (which helps form blood vessels)

Question 13

Menkes disease

Answer 13

problems with copper absorption and transport. causes intellectual disability, growth problems, hypotonia, and kinky, brittle hair.
decr. activity of lysyl oxidase (enzyme critical for collagen cross-linking)

Question 14

Elastin: important amino acids

Answer 14

proline and glycine. involves tropoelastin with fibrillin scaffolding. crosslinking also important (extra-cellular). broken down by elastase, which is normally inhibited by alpha-1 antitrypsin.
alpha-1-antitrypsin deficiency can cause emphysema and liver disease. problems with fibrillin sheak cause marfan syndrome.

Question 15

CDKs vs. cyclins

Answer 15

CDKs: cyclin dependant kinases that are CONSTITUTIVE and INACTIVE.
cyclins: regulatory proteins that control cell cycle events, are phase specific, and activate CDKs.

Question 16

microtubules vs. cilia vs intermediate filaments

Answer 16

microtubules: helical array of alpha and beta tubulin heterodimers. used for MOVEMENT: flagella, cilia, mitotic spindles, slow axonal transport. cilia have 9+2 arrangement of microtubles (other small details but I may not learn them)
intermediate tubules: used for STRUCTURE, and important becasue we stain them (GFAP, vimentin, desmin, cytokeratin, etc).