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31

RNA pols

In eukaryotes, I - rRNA, II - mRNA, III - tRNA (in ORDER); alpha-amanitin (Amanita phalloides) -| RNA pol II -> hepatotoxicity;
Prokaryotes only have one RNA pol that does it all

32

RNA processing

heterogeneous nuclear RNA = initial; 5' cap (t-methylguanosine), polyadenylation (~200), splicing, then leaves nucleus as mRNA

33

mRNA quality control occurs where? And contains what?

Cytoplasmic P-bodies - contain exonucleases, recapping enzymes, microRNA's

34

Polyadenylation signal?

AAUAAA

35

Intron vs. exon?

EXon = EXPRESSIVE; INtron is INTRUSIVE

36

Splicing works how?

snRNP's + others bind to form spliceosome, lariat intermediate; removal. anti-snRNP's ~ SLE

37

Where on tRNA is aa bound?

CCA (Can Carry Aa's) on 3' end

38

tRNA structure?

5' to D-arm (recog by aminoacyl-tRNA synthase; contains dihydrouracil residues) to Anti-codon loop to T-arm, which has thymine, pseudouridine, cytidine sequence for tRNA-ribosome binding

39

Enzyme responsible for charging tRNA?

aminoacyl-tRNA synthetase (requires ATP); good proofreading

40

Ribosome's sites for translation.

APE - A for incoming aminoacyl-tRNA, P for growing peptide, E for exit (holding)

41

ATP and GTP uses in translation?

ATP for charging; GTP for initiation and translocation

42

Cell cycle types (3)?

Permanent - Always in G0 and must regen from stem cells (Neurons, skeletal and cardiac m., RBCs)
Stable - Enter G1 from G0 when stimulated (hepatocytes, lymphocytes)
Labile - Never go into G0; short G1 (bone marrow, gut epithelium, skin, hair follicles, germ cells)

43

Function of RER?

Synthesis of secretory proteins; Called Nissl bodies in neurons

44

Functions of Golgi?

Distribution and modification; N-oligosaccharide mod on spargine, adds O-oligosaccharides on serine and threonine, adds mannose-6-phosphate for lysosomal trafficking

45

I-Cell disease

Failure of golgi to phosphoorylate mannose residues on glycoproteins that are intended for lysosomal trafficking; Instead secreted. Coarse facial features, clouded corneas, joint, high plasma levels of lysosmal enzymes

46

What vesicular trafficking proteins are involved in which areas?

Clathrin: trans-Golgi to lysosome; PM -> endosomes. COPI: retro golgi; Golgi -> ER. COPII: antero golgi; ER -> Golgi. Cops head backwards first!

47

Function of peroxisome?

Catabolizes VLCFAs, branched-chain FA's, AA's

48

Molecular motor directions?

Kinesin: Anterograde towards positive; Dynein: retrograde towards negative

49

What makes up microtubules?

alpha, beta tubulin; GTP

50

Drugs that act on MT's

Mts Get Constructed Very Poorly: Mebedazole, Griseofulvin, Colchicine, Vincristine/Vinblastine, Paclitaxel

51

Cilia structure

9+2 (9 doublets, 1 doublet inside)

52

Primary ciliary dyskinesia (Kartagener syndrome)

Immotile cilia b/c of dyne in arm defect of dyne in; infertility, bronchiectasis, sinusitis, situs inversus

53

Intermediate filament immunohistochemistry

Vimentin - connective tissue; Desmin - muscle; Cytokeratin - epithelial cells; GFAP - neuroglia; neurofilaments - neurons

54

Drugs that act on Na-K pump?

Ouabain inhibits by binding K+ site
Cardiac glycosides (digoxin) directly inhibits --> indirect inhibition of Na/Ca exchange -> inc Ca -> increased cardiac contractility

55

Four types of collagen

Be (So Totally) Cool, Read Books
I - Bone, Skin, Tendon, dentin, fascia, cornea, SCAR tissue
II - Cartilage, vitreous humor, nucleus puposus
III - Reticulin - skin, lungs, intestines, bone marrow, Granulation tissue, blood vessels, uterus
IV - basement membrane, basal lamina, lens

56

4 Major Diseases due to collagen problems?

Scurvy - Vit C required for hydroxylation; presents with bleeding gums, ecchymoses, impaired wound healing
Ehlers Danlos - vascular type (III); problems in cross-linking
Menkes - Impaired Cu absoprtion and transport (cross-linking problem b/c of lysyl oxidase);
Osteogenesis imperfecta - AD is dec prod of type I (fx, blue sclera, hearing loss, dental imperfections); triple helix bad
Alport syndrome - IV; Goodpasture syndrome - Ab against IV

57

Collagen synthesis

Synthesis (Gly-X-Y), Hydroxylation (scurvy), glycosylation and formation of pro collagen via H and S-S bonds to form triple helix (osteogenesis imperfecta), exocytosis, Proteolytic processing (procollagen -> insoluble tropocollagen via N- and C- peptidases), fibril assembly, cross-linking (covalent linkages lysine-hydroxylysine with Cu2+ containing lysyl oxidase) to make collagen fibrils

58

Marfan syndrome's etio?

Defect in fibrillin; glycoprotein that sheathes elastin

59

Three main steps for PCR?

Denature, Anneal primers, Elongation

60

Purpose of ELISA

Used to detect presence of a specific Ag (Direct) or Antibody (indirect) in patient's blood;
Direct Detects antiDen (b/c antibody sounds weird)