Flashcards in Biochemistry Deck (255)
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
heterogeneous nuclear RNA = initial; 5' cap (t-methylguanosine), polyadenylation (~200), splicing, then leaves nucleus as mRNA
mRNA quality control occurs where? And contains what?
Cytoplasmic P-bodies - contain exonucleases, recapping enzymes, microRNA's
Intron vs. exon?
EXon = EXPRESSIVE; INtron is INTRUSIVE
Splicing works how?
snRNP's + others bind to form spliceosome, lariat intermediate; removal. anti-snRNP's ~ SLE
Where on tRNA is aa bound?
CCA (Can Carry Aa's) on 3' end
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
Enzyme responsible for charging tRNA?
aminoacyl-tRNA synthetase (requires ATP); good proofreading
Ribosome's sites for translation.
APE - A for incoming aminoacyl-tRNA, P for growing peptide, E for exit (holding)
ATP and GTP uses in translation?
ATP for charging; GTP for initiation and translocation
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)
Function of RER?
Synthesis of secretory proteins; Called Nissl bodies in neurons
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
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
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!
Function of peroxisome?
Catabolizes VLCFAs, branched-chain FA's, AA's
Molecular motor directions?
Kinesin: Anterograde towards positive; Dynein: retrograde towards negative
What makes up microtubules?
alpha, beta tubulin; GTP
Drugs that act on MT's
Mts Get Constructed Very Poorly: Mebedazole, Griseofulvin, Colchicine, Vincristine/Vinblastine, Paclitaxel
9+2 (9 doublets, 1 doublet inside)
Primary ciliary dyskinesia (Kartagener syndrome)
Immotile cilia b/c of dyne in arm defect of dyne in; infertility, bronchiectasis, sinusitis, situs inversus
Intermediate filament immunohistochemistry
Vimentin - connective tissue; Desmin - muscle; Cytokeratin - epithelial cells; GFAP - neuroglia; neurofilaments - neurons
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
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
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
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
Marfan syndrome's etio?
Defect in fibrillin; glycoprotein that sheathes elastin
Three main steps for PCR?
Denature, Anneal primers, Elongation