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41 Cards in this Set
- Front
- Back
- 3rd side (hint)
Genome
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all the genes in the organisms DNA
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L3
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Proteome
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all the encoded proteins
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L3
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peptide
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short polypeptide
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gene
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an unbroken DNA nucleotide sequence that nearly always encodes a polypeptide
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L6
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transcription
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making an RNA copy of a gene, tiny parts of a DNA strand each encoding a polypeptides
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L-6
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asdf
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asdf
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translation
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directs the synthesis of the polypeptide amino acids sequence from the RNA gene copy (messenger RNA,mRNA) using transfer RNA (tRNA) and ribosomes, particles containing ribosomal RNA (rRNA)
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L-7
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Reverse transcription
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RNA copied to DNA in retroviruses
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L-7
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The 5' phosphate is attached to the 3' end of the preceding nucleoside by _____
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phosphodiester bonds (as in DNA synthesis)
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L-8
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5 differences b/t RNA and DNA
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1. the ribose retains OH at its 2' position
2. the bases have uridine instead of thymidine 3. RNA is always single stranded 4. Complementary regions may fold back on themselves, forming double helical regions. 5. RNA free protein, for example mRNA, is hydrolyzed by alkali |
L-9
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requirements of DNA dependent RNA polymerase
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These are the core polymerase enzymes
double stranded DNA, one Zn2+ ion for NTP binding and Mg2+ ions for catalysis four nucleotide 5'triphosphates (ATP, GTP, CTP, and UTP) RNA chain extends from 5' to 3' catalysis is by 3'-OH end attacking 5'-phosphate of incoming NTP |
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summary of steps in bacterial RNA synthesis
(pg L-15) |
1. transcription starts when sigma factors binds to a promoter consensus sequence.
2. RNA core polymerase binds sigma factor and unwinds DNA. 3. Transcription bubble (17bp) forms 4. RNA bases are selected by hybridizing to the DNA template and extend progressively from 3' to 5' end 5. Single RNA strand has same sequence as DNA coding strand complimentary to the template 6. Two termination sequences: hairpin structure (self-complementary) or rho (p) protein binding |
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RNA Pol I
(pg. L-16) |
transcribes ribosomal RNA genes in nucleous
(products are not transcribed) |
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RNA Pol II
(pg L-16) |
transcribes pre-messenger RNA in the nucleoplasm. Pol II attaches more polypeptide cofactors than bacterial RNA polymerase and recognizes promoters that are much more varied in sequence than bacterial promoters
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RNA pol III
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transcribes tRNA and most small RNAs
(products are not transcribed) |
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RNA POl IV
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transcribes mitochondrial (non-nuclear) DNA. It resembles bacteriophage RNA polymerases.
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---- region TATA box: binds _____ subunit factor
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-10 region, sigma 70 subunit factor
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what are RNA polymerase core enzyme four subunit functions
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alpha- assembly
beta- catalysis beta'- binding of template omega- chaperone |
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sigma protein function
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binds promotor sequences on DNA to initiate RNA synthesis
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Rho protein function
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binds terminator RNA sequences adn stops RNA sythesis
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mode of action of Actinomycin D
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inhibits all RNA transcription b/c it binds to certain (GpC) sequences in DNA, preventing the open transcription complex from forming
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Rifampicin mode of action
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binds to the active site of bacterial but not eukaryotic RNA polymerase
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a-amanitin mode of action
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binds strongly to RNA Pol II, inhibiting eukaryotic but not bacterial mRNA transciption
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type of RNA not in prokaryotes
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-snRNA b/c there processing of bacterial mRNA
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types of RNA in eukaryotic cell, from greatest amount to least amounts present
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rrRNA > tRNA > mRNA > snRNA > scRNA
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Splicesomes are composed of ______.
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snRNA particles
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splicesomes attach to RNA Pol ____
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II
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function of cap and tail in eukaryotic mRNAs
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CAP- facilates splicing
TAIL- facilitates mRNA transport out of the nucleus -Both facilatate initiation of translation by attaching to the ribosomal small subunit |
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Exosome is a
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protein exonuclease particle that digests all types of RNA from 3' to 5'
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spliceosome
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is an snRNA particle that removes introns as eukaryotic mRNA is being synthesized
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Proteasome
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is a protein particle that digest ubiquitinylated proteins in the cytosol
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sizes of ribosomal particles or their compnent RNAs are measured in
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Svedbergs, a sedimentation coefficient measurement
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what enzymes synthesizes eukaryotic ribosomes?
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the DNA gene encoding eukaryotic ribosomal RNA are transcribed by RNA POLYMERASE I
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Enzymes required to process mRNA?
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a. Phosphohydrolase, Guanosyl transferase, and Methylase (cap)
b. Polyadenylate polymerase complex containing endonuclease and polyA polymerase (tail) c. Small nuclear RNA particles with consensus binding sequences (splicosomes) |
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What enzymes are required to process freshly synthesized tRNA and rRNA
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SPECIFIC ENDO- AND EXO-NUCLEASES that trim the ends and may also be required to remove an intron
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what are the consensus residues taht identify an intron and are mecessary for its removal from freshly synthesized RNA?
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the first two residues at the 5' END,
and the last two at the 3' END and an ADENOSINE RESIDUE about TWO-THIRDS of the way towards the 3' end |
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One gene can encode two different polypeptides. How?
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1. Alternative splicing
2. Limited proteolytic processing |
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function of the cap in eukaryotic mRNAs
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facilitates splicing
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function of tail in eukaryotic mRNAs
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facilates mRNA transport out of the nuclues
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what function does the tail and cap in eukaroytic mRNA have in common
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both facilitate the initiation of translation by attaching to the ribosomal small subunits
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where are ribosomes and proteins synthesized in Eukaryotic cells
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Ribosomes- made in nucleolus of the nucleus
proteins- in the cytosol, often attached to the rough endoplasmic reticulum |
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