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Flashcards in Biochem - cellular Deck (16):
1

Inhibitors of G1-to-S progression

p53 and hypophosphorylated Rb

2

failure of Golgi to phosphorylate mannose --> coarse facial features, clouded corneas, restricted joint movement

I cell disease

inherited lysosomal storage disorder

3

COP1 vs. COP2 vs. clathrin

COP1 - retrograde, Golgi to ER
COP2 - ER to Golgi
clathrin - Golgi to lysosome, plasma membrane to endosome

4

Structure of microtubules

heterodimers of alpha and beta tubulin

each dimer has 2 GTP

5

Dynein vs. kinesin

Dynein - retrograde to microtubule (+ to -)
Kinesin - anterograde to microtubule (- to +)

6

Collagen found in bone, skin, tendons

Type 1

decr. in osteogenesis imperfecta

7

Collagen found in cartilage

Type 2

8

Collagen found in reticulin, blood vessels

Type 3

deficient in vascular type of Ehlers-Danlos

9

Collagen found in basement membrane

Type 4

Defective in Alport syndrome (nephritic syndrome)

10

Six steps of collagen synthesis

Synthesis
Hydroxylation
Glycosylation
Exocytosis

Proteolytic processing
Cross-linking

11

Translation of collagen alpha chains

Collagen Synthesis (occurs in the RER)

Gly-X-Y (collagen is 1/3 glycine)

12

Hydroxylation of proline and lysine residues

Collagen hydroxylation (occurs in the RER)

REQUIRES VITAMIN C - def. = scurvy

13

Formation of procollagen via hydrogen and disulfide bonds into a triple helix

Collagen glycosylation (occurs in the RER)

Problems forming triple helix (osteogenesis imperfecta)

14

Cleavage of disulfide-rich terminal regions of procollagen in tropocollagen

Proteolyic processing

occurs outside fibroblasts

15

Reinforcement of tropocollagen by lysine-hydroxylysine cross-linkage to make collagen fibrils

Cross-linking

required copper-containg lysyl oxidase (defective = Menkes disease, look for brittle/kinky hair, growth retardation, hypotonia)

16

Defect found in Marfan syndrome

Fibrillin - glycoprotein that forms a sheath around elastin