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43 Cards in this Set
- Front
- Back
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Purine
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A or G
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Pyrimidine
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T or C
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Nucleoside
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nitrogenous base and a sugar
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Nucleotide
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Nitrogenous base, sugar and phosphate group
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Which letter represents the right handed twist conformation DNA?
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A and B
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Which letter represents the left handed twist conformation DNA?
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Z
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what composes a histone core?
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two copies of: H2a, H2b, H3 and H4
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what is the nucleosome made of?
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histone core (two: H2a, H2b, H3, H4), 147 pairs of DNA and an H1 molecule
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describe euchromatin
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open structure which stains poorly
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describe heterochromatin
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condenced structure and stains well with many dyes. inactive for transcription due to tight coils and is methylated or deacetylated
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describe gene structure of prokaryote
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polycisteronic= 1 promoter directs synthesis of 1 mRNA that is translated to more than one polypeptide.
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describe gene structure of eukaryotes
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monocisteronic= 1 promoter directs synthesis of 1 mRNA that translates generally to only ONE PROTEIN!
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def topoisomerase type 1
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unwinds super coils in the DNA helicase
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def DNA polymerase
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fills in gap with DNA except int he break of backbone between 3'OH and the 5'PO4 ends
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Def: RNAse H
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removes the RNA primer (degrades Hybrid RNA:DNA leaving a gap in the dsDNA)
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Def: Ligase
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Repairs the niche with a phosphodiester bond between 5'PO4 and 3'OH, connecting the DNA 3' ends to the heavier DNA 5' ends
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Def topoisomerase type II
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required to seperate in daughter DNA just after DNA replication of circular chromosomes
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Def: Telomeres
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ends of eukaryotic chromosomes. TG rich read t repeats, confer stability on DNA molecule. protection
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Def: telomerase
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multiple protein subunits and an RNA component which extends the 3'OH end of the substrate. doesnt require an exogeneous DBA template to add dNTPs.
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whats bad about high telomerase activity in cells
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highly active in cells= increased replication capacity (cancer) essential in cells immoratality.
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Def: processicity
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rate of rapidness
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def: semi-discontinuous
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leading strand is cont. lagging strand is not, the overall is semi
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def: semi-conservative
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1 new strand and 1 old strand is present in new DNA
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def Leading strand
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the stand that runs 5'-->3' (and gets duplicated 3'-->5')
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def lagging strand
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the opposite DNA stand that is forced to run 3'-->5' on the template (and replicated 5'-->3') in many small fragments that have to be spliced together
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def: Okazaki fragment
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a piece of DNA created on the lagging strand of DNA replication sequence. a transient intermediate.
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def: start (initiation) site of replication
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DNA base pair where transcription initiates
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Def: promoter
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TTGACA or TATAAT box, helps the RNA polymerase to adhere to the start sequence AUG
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what is RNA polymerase
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enzyme that catalyzes transcription. combines with sigma factor to create RNA polymerase holoenzyme, recognizes the promoters and initiates transcription.
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what are the components of the E. coli RNA polymerase?
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large unit (core polymerase): two of each: alphas, betas, beta primes, omegas
smaller subunit: sigma factor |
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name the three types of RNA polymerases in eukaryotes
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RNApoly 1
RNA poly 2 RNApoly 3 |
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which class of RNA is transcribed by the eukaryotic RNApoly1?
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Pre-rRNA (80%)
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which class of RNA is transcribed by the eukaryotic RNApoly2?
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pre-mRNA (1-5%)
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which class of RNA is transcribed by the eukaryotic RNApoly3?
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Pre-tRNA (15%)
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Def: Sense strand
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the RNA strand that is unbroken during translation 3'-->5' on new RNA strand
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Def: Non-sense strand (Anti-sense)
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the RNA strand that gets made "backwards" (5'->3' on the RNA) and in sections that need to be spliced together.
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Def: template strand
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the DNA strand that serves as a backbone for RNA replication
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def: what is the start site
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AUG
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Def: Promotor
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helps the RNA polymerase to bind to the start site
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Def: RNA polumerase
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the enzyme which produces the RNA
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Def: holoenzyme
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the main conponent that makes up the RNA polumerase
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Def: Transcription factors
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factors involved in initiation to have the RNA polymerase
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Def: CTD Tail
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Carbocyterminal domain tail. large subunit of RNA poly II that contains a series of peptide sequence repeasts. its a site for phosphorylation and controls elongation and shedding of TFs used for initiation.
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