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20 Cards in this Set
- Front
- Back
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first two steps of biological information
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transfer,replication,transcription:synthesis of NA using NA templates
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last step of biological information
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transfer,translation:assembly of aa into a protein on a NA template,mRNA.
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aa dont repair with bases of nucleotides
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the template provides info thru the genetic code which is the blueprint for assembly of the corresponding polypeptide from the aa's
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the universal genetic code
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1.RNA triplet code
2.non overlapping 3.degenerate:several codons code from same aa 4.start/stop codons 5.in bacteria the genus is mycoplasma, and in eukarya the genus of paramecium |
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aminoacylation of tRNA by its cognate aminoacyl-tRNA synthetase
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aa + tRNA + ATP->(synthetase)
aminoacyl-tRNA + AMP + PP |
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shine-dalgarno sequences
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sequence at 3' of 16S rRNA
(euk:5'cap on mRNA is recognized by 40S) mRNA leader and 16S rRNA pairing |
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deviation from genetic code(1)
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in prok and euk selenocysteine (SECys) is inserted into polypeptides when the UGA codon appears in mRNA(affects small # of prot)
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deviation from genetic code(2)
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in methanogenic arachaea and bacteria UAG codes for pyrrolysine, the 22nd aa
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deviation from genetic code(3)
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in the mycoplasma, phycoplasma and the mito of the ascomycetes UGA codes for trp.
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deviation from genetic code(4)
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in the mito of mammals:
UGA-trp AGA,AGG-stop AUA-met |
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deviation from the genetic code(5)
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in the mito of budding yeast saccharomyces cerevisiae:
UGA-trp AUA-met CUX-thr |
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wobble pairing
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complementary base pairing bw tRNA anticodons and mRNA codons(reduces the number of tRNA required to translate a degenerate genetic code)
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protein folding:chaperones and chaperonins
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(prots that help other prots to fold correctly)
heat shock:best known (Hsp) ie:shock ecoli w/ high temp to gain capacity to survive for long time at higher temp(but < what you shocked it at) |
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chaperones
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best bacterial:DnaK which is a Hsp70
DnaK:required for assembly of the wavelength rep, is a heat shock sensor and regulates the synthesis of other prot. DnaK null mutants:survive but grow slow,trigger factor folds prot as they emerge from ribos can sub for DnaK |
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chaperonins
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best characterized:GroEL that acts with 1 co-chaperonin,GroES as a chamber that provides the environment for the folding of other prot. including the wavelength phage head E protein.
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posttranslational protein processing
(after translation many new polypeptides are modified or processed before they become active) |
1.formyl group removed from N-formyl methionine
2.methionine at N-term removed 3.signal seq are cleaved from prot during translocation across membranes |
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posttranslational protein process 4-6
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4.virus proteins were produced as polyproteins which are cleaved into active pdts
5.prot can be modified by attachment of sugars to lipids to yield glycoprot and lipoprot 6.inteins removed and exteins sliced during maturation (GyrA) |
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protein splicing
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441 aa long intein of GyrA polypeptide of M.leprae is protease that plices itsef from the GyrA preprotein yielding the mature GyrA subunit and a free form of itself which is degraded.
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antibiotics that inhibit translation
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streptomycin:blocks chain intiation by 30S(2hex,pent)
chloramphenicol:blocks peptide bond formation on 50S(hex w/ Cl,OH,N R's) cycloheximide:inhibits peptide elongation in eykaryotes used to treat fungal and protozoan infections. |
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antibiotics that inhibit translation continued
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tetracycline:blocks elongation by binding into site A on 30S(4hex)
puromycin:binds into A site and causes peptide release from 50S(hex,pent,shit bw) kanamycin:very broad abiotic,binds 16S rRNA(chair configurations) |
