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54 Cards in this Set
- Front
- Back
Differences between Eukaryotic and Prokaryotic Translation?
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1. scans mRNA for first AUG
2. eukaryotic ribosomes are larger 3. Initiation: -eukaryotes have no ribosome binding site, cap is recognized -met-tRNA instead of formyl-Met-tRNA |
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IF1
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prevents tRNA from binding to the portion of the small subunit that will become part of the A site by binding to the A site
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IF2
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GTPase that interacts with small subunit, IF1, and initiator tRNA. Facilitates their association and prevents other tRNAs from associating.
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IF3
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prevents formation of 70S ribosomes from 30S and 50S subunits.
Occupies E site. |
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70S initiation complex
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last step of initiation, which is association of the large subunit to the small subunit after start codon and initiator tRNA base pair and IF3 is relased by conformational change in small subunit
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function of α-C-terminal domain
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interacts with UP element
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mediator complex
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multi-protein complex that mediates between proteins and the pre-initiation complex
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B-DNA
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most stable configuration
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Top IV
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Type II topoisomerase
ATP-Dependent cuts both strands |
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DNA Gyrase
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Type II topoisomerase
ATP-Dependent introduces negative supercoils |
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Top I
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Type I topoisomerase
ATP-Independent passes ONE strand through another |
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Top III
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Type I topoisomerase
ATP-Independent passes ONE strand through another |
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Rank from traveling far to less traveling:
Nicked Circle DNA, Linear, Supercoiled |
Supercoiled> Linear > Nicked Circle
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Modifications of N-terminal tails to make histones fall off and allow access to chromosomes:
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acetylation of lysines
phosphorylation of serines |
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ssB
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single stranded binding protein.
binds to single strands to prevent reformation of double helix and hairpins from forming |
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RNase H
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removes RNA primers
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DNA Pol I
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removes RNA primers and fills gap with DNA
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DNA Pol III
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highly processive, synthesizes DNA starting at RNA primers
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Ligase
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fixes nicks in backbone, uses ATP
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helicase
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unwinds DNA, requires ATP and DnaC to load
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DNA Pol III holoenzyme accuracy
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1) without correct base pairing the incoming dNTP is not positioned correctly for the reaction to occur
2) the 2'-OH of ribonucleotides don't fit in the active sit 3) 3'->5' exonuclease activity removes misincorporated bases |
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DnaB
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helicase
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DnaC
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loader for DnaB(helicase)
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DnaG
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primase
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DnaA
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replication initiation factor
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Dam
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DNA Adenine Methyltransferase
finds sequences GATC and adds a methyl group to the A, which protrudes into the major groove |
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seqA
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binds hemimethylated oriC, preventing DnaA binding and dam methylation
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Replication Initiation Controlled by:
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1)DnaA-ATP levels
2)control of access to oriC (seqA) |
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Eukaryotic DNA Replication differences:
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-replisome moves more slowly
-multiple ori -less known -chromosomes end up shorter after each round |
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Telomerase
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ribonucleoprotein, reverse transcriptase
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-35 and -10 promoters
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-35: TTGACA
-10: TATAAT |
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RnaseP
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catalyzes maturation of 5' terminus of tRNA
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RNA Pol I
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rRNA
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RNA Pol II
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mRNA
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RNA Pol III
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tRNA
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Eukaryotic Transcription differences
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-3 RNA Polymerases
-mRNA is monocistronic -mRNA is capped and polyadenylated -splicing of mRNA |
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HAT
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Histone acetyl transferase
-decreases affinity of histones for chromosomes |
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transition mutation
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pyrimidine to pyrimidine
purine to purine T to C A to G |
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transversion
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pyrimidine to purine
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MutS
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scans DNA for mismatch repair system, recognizes mismatches from the distortion they cause in the backbones
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MutH
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activated by MutL, causes a nick on one strand near the site of the mismatch
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MutL
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recruited by MutS, required to recruit MutH
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GTPase
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protein that binds and hydrolyses GTP
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aminoacyl-tRNA synthetase
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charge tRNAs with amino acids
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where is amino acid attached to tRNA
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3' terminus at CCA sequence
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IF1
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prevents tRNA from binding to the A site
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IF2
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facilitates association of initiator tRNA with P site and prevents other tRNA from blocking the P site
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IF3
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binds to small subunit and blocks in from associatin with the large subunit
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EF-Tu-GTP
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escorts charged tRNA to A site
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factor binding center
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does GTP hydrolysis and creates EF-Tu-GDP which dissociates
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EF-G-GTP
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moves peptidyl-tRNA from the A-site to the P-site during translocation. drives translocation by replacing tRNA in the A site.
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EF-Ts
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stimulates release of GDP from EF-Tu so that EF-Tu can bind GTP again.
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Eukaryotic Translation Differences
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1) binding of initator tRNA in small subunit precedes association with mRNA
2) separate set of factors mediates recognition of mRNA 3) scans for first AUG sequences 4)initiator is methinione 5) no RBS |
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peptide bond formation
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catalyzed by 23S rRNA
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