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98 Cards in this Set
- Front
- Back
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Required for ribose 5-p to prpp?
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glycine, aspartate, glutamine, THF
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mechanism of 6-MP
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blocks de novo purine synthesis (IMP)
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what makes orotic acid?
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carbamoyl phosphate
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required to make UMP form oritic acid and PRPP
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aspartate
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role of ribonucleotide reductase
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UDP to dUDP
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role of thymidylate synthase
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dUMP to dTMP
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role of dihyrofolate reductase
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DHF to THF
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mechanism of 5-Fu, what lowers
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inhibits thymidylate synthase, low dTMP
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mechanism of methotrexate, what lowers
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inhibits DHF-reductase, low dTMP
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mechanism of TMP, what lowers
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inhibits bacterial DHF-reductase, low dTMP
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orotic aciduria is a defect in what?
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conversion of orotic acid to UMP i.e. de novo pyrmidine synthesis
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findings in orotic aciduria?
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megaloblastic anemia, failure to thrive, orotic acid in urine
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treatmeant of orotic aciduria
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uridine
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required to convert Guanine to GMP?
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HGRPT + PRPP
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required to convert hyoxanthine to IMP?
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HGRPT + PRPP
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required to conver Adenine to AMP?
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APRT + PRPP
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Required to convert Adenosine to ionosine?
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adenosine deaminase
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how is uric acid made?
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guanine and hypoxantine (purine salvage pathway) are converted into xanthine and then uric acid by xanthine oxidase
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required to convert hypoxanthine/guanine to xanthine/uric acid?
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xanthine oxidase
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mechanism of adenosine deaminase deficiency?
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Excess ATP/dATP: can't make adenosine into hypoxanthine, so ATP builds up. This ATP blocks ribonucleotide reducatse> halts DNA synthesis> decreased lymphocyte count (rapidly dividing)> SCID
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mechanism of lesch-nyan?
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Absence of HGRPT. Can't convert purine products back into purine, turn them into uric acid instead.
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findings in lesch-nyhan syndrome?
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aggresion, self-mutalation, gout, retardation, hyperurachemia, coreoathetosis
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genetics of lesch-nyan?
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x-linked recessive
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genetic code features: unabiguous?
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each codon= only 1 amino acid
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genetic code features: degenerate/redudant:
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more than 1 code for the same amino acid
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which aa is not redundant?
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methionine (AUG)
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in which organisms/parts is the genetic code are not conserved?
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mitochondria, archaebacteria, mycobacteria, some yeast
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what is a silent mutation?
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same amino acid
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what is a missence mutation?
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change amino acid
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what is a nonsense mutation?
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make it stop
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what is a frame shift mutation?
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everything downstream wrong
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role of helicase?
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unwind DNA
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role of DNA topoisomerases
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knicks in DNA so it doesn't supercoil
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DNA polymerase III vs. I?
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Polymerase III goes first and has 3' to 5' exonuclease activity
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Nucleotide excision repair
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exonuclease> remove damaged base> DNA polymerase> fill gap> DNA ligase> seals
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mechanism of xeoderma pigmentosa?
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mutaded nucleotide excision repair of thymidine dimers, causing dry skin w/ melanoma
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what is DNA repair mechanism is mutated in HNPCC?
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mismatch repair
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how do drugs cause chain termination blocking DNA replication?
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they mutated the 3' OH
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base excision repair?
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glycosylase> remove damaged bases> endonuclease cut DNA> empty sugar removed> gap filled and resealed
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start codone?
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AUG-methionine
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mRNA stop codons?
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UGA, UAG, UAA
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gene promoter rich in which bases?
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AT
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what is the role of the enhancer region of gene
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transcription factors bind
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what is the role of silecers in genes?
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repressors bind
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what is alpha-amantin
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it is in mushrooms. It causes liver failure by inhibting RNA polymerase II (makes mRNA)
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post transcriptional modification of RNA?
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5' CAP, 3' PolyA tail, introns spliced out
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patients w/ lupus make ab to what?
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splicesomal -SNRP (splicing of pre-mRNA)
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exons vs. introns?
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exons are actually expressed, introns are spliced out
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mechanisms of tetracyclines?
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bind 30 s subunit, preventing attachment of aminoacyl-tRNA
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ATP role in protein synthesis?
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charging tRNA w/ amino acid (tRNA activation)
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GTP role in protein synthesis
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translocation
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aminoglycosides mechanism of action
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at 30s- prevent initiation of protein synthesis
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macrolides mechanism of action
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bind 50s- prevent translocation
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chloramphenicol mechanism of action?
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inhibit peptidyltransferase in 50s, prevent transolcation
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clindamycin mechanism of action
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binds 50s-prevents translocation
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tetracyclines mechanism of action?
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bind 30s, preventing initiation of protein synthesis via preventing aminolacyl-tRNA attachment
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shortest phase of cel cycle?
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mitosis
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role of cyclins?
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activate CDKs, which then allows progression through the cell cycle
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role of RB and p53 in cell cycle
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inhibit progression from G1 to S
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stable vs. labile cells
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stable- hang out in G0 until signal received; labile- never go into G0, short time in G1, rapid progression through cell cycle
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name some permanent cells
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RBC, neuron, cardiac muscle, skeletal muscle
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name stable cells
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hepatocytes, lymphocytes
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where are secretory proteins made?
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RER
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what are nissl bodies?
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RER in neurons, they make enzymes and peptide neurotransmitters
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where are cytosolic and organellar proteins made?
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free ribosomes
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where are steroids synthesized?
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SER
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where are drugs and poisions detoxified?
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SER
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how/where are proteins targeted for lysosomes
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add mannose-6-phosphate in golgi
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role of clarithin?
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endocytosis-move from golgi to lysosome/plasma membrane> endosomes
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what is i-cell disease?
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defect in adding mannose-6-phosphate to proteins that should go to lysosome, they are excreted instead
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features of i-cell disease
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coarse facial features, stiff joints, clouded corneas, high plasma lysosomal enzymes. Can be fatal in childhood
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use/general mechanism of mebendazole/thiabendazole?
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anti-worm; acts on microtubules
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use/general mechanism of colchicine?
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gout; acts on microtubules
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use/general mechanism of paclitaxel?
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breast cancer; acts on microtubules
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use/general mechanism of griseofulvin?
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anti-fungal; acts on microtubules
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use/general mechanism of vincristine/vinblastine?
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anti- cancer; acts on microtubules
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genetics of chediak-higashi syndrome?
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autosomal-recessive, rare
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partial albinism, recurrent pyogenic infections, partial albinism, peripheral neuropathy?
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chediaki-higashi
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mechanism of chediak-higashi syndrome?
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lysosomal trafficking defect due to microtubule polymerazation--> decreased phagocytosis
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kartagener's syndrome?
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immotile cilia due to dynein arm defect resulting in infertility, bronchiectasis, recurrent sinusitis; associated w/ situs invertus
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ouabain?
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inhibits NA/K/ATPAse by binding ot K+ site, poisoinous cardiac glycoside
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mechanism of digoxin?
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cardiac glycoside- directly inhibits NaKATPase> inhibiton of Na/Ca exchange> increase intracellular Ca> inc cardiac contractility
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type IV collagen where?
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basement membrane
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Type II collagen where?
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cartilage/nucleus pulpusus
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type III collagen where?
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(reticulin)-granulation tissue, skin, uterus, fetal tissue, blood vessels
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where is collagen synthesized?
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RER
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where does hydroxylation of proline and lysine in collagen take place? What is required? Dz?
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ER; vitamin C; scurvy
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how is procollagen formed? Where? Dz?
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glycosylation of pro-alpha-chain lysine residues (triple helix); ER; osteogenesis imperfecta
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how is tropocollagen formed? What is it? Dz?
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post-fibroblast cleavage; insolouble form of collage; Ehlers-Danlos
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type of collagen most effected by ehler-danlos
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type III (tropocollagen)
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mutliple factures w/ minimal trauma; blue sclera; hearing loss; dental imperfections
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osteogenesis imperfecta (glycosylation- procollagen)
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hypermobile skin and joints, easy brusing/bleeding/berry aneurysms
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Ehler-Danlos
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progressive hereditary neprhitis and deafness
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Alport's syndrome
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most common for of osteogenesis imperfecta has defect in what type fo collagen?
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type I
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what collagen is involved in alport's syndrome?
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Type IV
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role of alpha1-antitrypsin
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inhibits elastase> elastin not broken down
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alpha-1 antitrypsin deficiency?
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no elastase inhibition> elastin broken down> emphysema (lung broken down)
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cause of marphans?
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defect in fibrilin, a component of elastin
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