In#2009,#Nobel#Prize#in#Chemistry#was#awarded#for#which#of#the#fol lowing?#A. Determining#the#structure#of#RNA#Polymerase#B. Determining#the#structure#of#the#ribosome#C. D iscovery#of#heatEresistant#DNA#Polymerase#Venkatraman)Ramakrishnan#MRC#Laboratory#of#Molecular#Biology,#Cambridge,#United#Kingdom##Thomas)A.)Steitz#Yale#University,#New#Haven,#CT,#USA#Ada)E.)Yonath#Weizmann#InsOtute#of#Science,#Rehovot,#Israel#"for%studies%of%the%structure%and%func0on%of%the%ribosome"#Venkatraman)Ramakrishnan,)UCSD)biology)graduate)student)1976D78#AnimaOons:#TranscripOon:#hRp://highered.mcgrawEhill.com/sites/0072507470/student_view0/chapter3/animaOon__mrna_synthesis__transcripOon___quiz_1_.html#TranslaOon:#hRp://vcell.ndsu.nodak.edu/animaOons/transl aOon/movieEflash.htm#List two components that are different between replication and transcription reactions (template, enzymes, product, etc). List two aspects that are similar. Examples of good answers: Differences: - Replication produces two identical polynucleotide strands, while transcription produces one polynucleotide strand - Product of replication is DNA, product of transcription is RNA. - RNA Polymerase synthesizes nucleic acids in transcription, DNA Polymerase synthesizes nucleic acids in replication - Replication differs from transcription by the fact that replication copies the entire DNA molecule, while transcription copies only a section of DNA onto a mRNA molecule Similarities: - Replication and transcription use the same base-pairing rules, except U substituting for T in transcription - 5’ to 3’ direction of nucleic acid synthesis - Both use DNA template for synthesis of a new nucleic acidExamples of incomplete/ambiguous answers Differences - Replication always adds from 5’ to 3’ direction - Replication: enzyme ligase, transcription: RNA Polymerase - Replication uses DNA polymerase, transcription does not - Replication uses enzyme - Enzyme versus promoter - Replication uses primase, transcription uses promoters Similarities - 5’-3’ direction - Both use RNA - Transcribe 5’-3’ - Template - Both make new strands - Both replicate somethingRNA Processing: In eukaryotes, mRNA end modifications added in the nucleus • The 5ʹ′ end receives a modified nucleotide cap. • The 3ʹ′ end gets a poly-A tail. A#modified#guanine#nucleoOde#added#to#the#5’#end#50#to#250#adenine#nucleoOdes#added#to#the#3’#end#ProteinEcoding#segment#PolyadenylaOon#signal#PolyDA)tail)Stop#Start#5’)Cap)AAUAAA#AAA…AAA#G#P#P# P#5’#3’#Bacterial genes consist of a single stretch of uninterrupted sequence. In eukaryotic genes, coding regions (exons) are interrupted by long noncoding sequences (introns)The)number)of)exons)in)human)genes)varies:)human)βDglobin)gene)has)only)3)exons,)while )hum an)Factor)VIII)(a)bloodDcloTng)prote in)) has)26)exons)RNA Processing: Split genes are spliced to make sense of mRNA RNA Splicing Removes “introns” -- Joins “exons” Figure)17.10)5’#Cap#Exon#Intron#1#30#31#Exon#Intron#104# 105# 146#Exon#PolyEA#tail#PolyEA#tail#Introns#cut#out#and#exons#spliced#together#Coding#segment#5’#Cap#1#146#PreDmRNA)mRNA)RNA Splicing is catalyzed by a large enzymatic complex called Spliceosome Figure)17.11)RNA#transcript#(preEmRNA)#Exon#1#Intron#Exon#2#Other#proteins#Protein#snRNA#snRNPs)Spliceosome)Spliceosome#components#CutEout#intron#mRNA#Exon#1#Exon#2#5’#5’#5’#1)2)3)Spliceosome contains both proteins and non-coding RNAs Ribozymes are RNAs that can act as enzymes Splicing#animaOon:#hRp://vcell.ndsu.nodak.edu/animaOons/mrnasplicing/movieEflash.htm#RNA)Processing:)Regulated)mRNA)transport)and)stability)in)cytoplasm)• UTR#sequences#control:##E where#mRNA#localized#E How#efficiently##mRNA#is#translated#E How#fast#mRNA#is#degraded#ProteinEcoding#segment#3’#UTR#Stop#Start#AAUAAA#AAA…AAA#G#P#P# P#5’#3’#5’#UTR#UTR#=#UnTranslated#Region#Which#of#the#foll owing#is#true#for#both#prokaryoOc#and#eukaryoOc#gene#expression?##A)#The#introns#are#spliced#by#spliceosomes#B)#TranslaOon#of#mRNA#can#begin#before#transcripOon#is#complete.##C)#RNA#polymerase#binds#to#the#promoter#region#to#begin#transcripOon.##D)#mRNA#is#synthesized#in#the#3'#→#5'#direcOon.##E)#The#mRNA#transcript#is#the#exact#complement#of#the#gene#from#which#it#was#copied.##TranslaYon:)mRNA)))))Protein)mRNA#sequence#of#bases#determines#protein#amino#acid#sequence#Figure)17.4)DNA#molecule#Gene#1#Gene#2#Gene#3#DNA#strand#(template)#TRANSCRIPTION)mRNA#Protein#TRANSLATION#Amino#acid#A) C) C)A) A) A) C) C) G) A) G)T)U) G) G)U)U) U)G)G) C)U) C)A)Trp)Phe)Gly)Ser)Codon#3’# 5’#3’#5’#Part#II#RNA)DD>)Protein#Cracking)the)Code)Codons#in#messenger#RNA#are#either###E#tran slated#into#an#amino#acid,#or###E#serve#as#a#translaOonal#“stop”#signal#Figure)17.5)Second)mRNA)base)U) C) A)G)U)C)A)G)UUU#UUC#UUA#UUG#CUU#CUC#CUA#CUG#AUU#AUC#AUA#AUG#GUU#GUC#GUA#GUG#Met#or#start#Phe#Leu#Leu#lle#Val#UCU#UCC#UCA#UCG#CCU#CCC#CCA#CCG#ACU#ACC#ACA#ACG#GCU#GCC#GCA#GCG#Ser#Pro#Thr#Ala#UAU#UAC#UGU#UGC#Tyr# Cys#CAU#CAC#CAA#CAG#CGU#CGC#CGA#CGG#AAU#AAC#AAA#AAG#AGU#AGC#AGA#AGG#GAU#GAC#GAA#GAG#GGU#GGC#GGA#GGG#UGG#UAA#UAG#Stop#Stop#UGA#Stop#Trp#His#Gln#Asn#Lys#Asp#Arg#Ser#Arg#Gly#U)C)A)G)U)C)A)G)U)C)A)G)U)C)A)G)First)mRNA)base)(5’)end))Third)mRNA)base)(3’)end))Glu#Figure)17.5)Second)mRNA)base)U) C) A)G)U)C)A)G)UUU#UUC#UUA#UUG#CUU#CUC#CUA#CUG#AUU#AUC#AUA#AUG#GUU#GUC#GUA#GUG#Met#or#start#Phe#Leu#Leu#lle#Val#UCU#UCC#UCA#UCG#CCU#CCC#CCA#CCG#ACU#ACC#ACA#ACG#GCU#GCC#GCA#GCG#Ser#Pro#Thr#Ala#UAU#UAC#UGU#UGC#Tyr# Cys#CAU#CAC#CAA#CAG#CGU#CGC#CGA#CGG#AAU#AAC#AAA#AAG#AGU#AGC#AGA#AGG#GAU#GAC#GAA#GAG#GGU#GGC#GGA#GGG#UGG#UAA#UAG#Stop#Stop#UGA#Stop#Trp#His#Gln#Asn#Lys#Asp#Arg#Ser#Arg#Gly#U)C)A)G)U)C)A)G)U)C)A)G)U)C)A)G)First)mRNA)base)(5’)end))Third)mRNA)base)(3’)end))Glu#What#amino#acid#sequence#will#be#generated,#based#on#the#following#mRNA#codon#sequence?#5'#AUGEUCUEUCGEUUAEUCCEUUG#3'##• A)#metEargEgluEargEglu Earg##• B)#metEgluEargEargEglnEleu##• C)#metEserEleuEserEleuEser##• D)#metEserEserEleuEserEleu##• E)#metEleuEpheEargEgluEglu##TranslaOon#• AnimaOon:#hRp://vcell .n dsu .no dak.edu /animaOons/translaOon/movieEflash
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