Fig b 0.25 µm Origin of replicationDouble-stranded DNA molecule Parental (template) strand Daughter (new) strand Bubble Replication fork Two daughter DNA molecules (b) Origins of replication in eukaryotes Eukaryotic replication

Fig Ends of parental DNA strands Leading strand Lagging strand Last fragment Previous fragment Parental strand RNA primer Removal of primers and replacement with DNA where a 3 end is available Second round of replication New leading strand New lagging strand Further rounds of replication Shorter and shorter daughter molecules

Fig Ends of parental DNA strands Leading strand Lagging strand Last fragment Previous fragment Parental strand RNA primer Removal of primers and replacement with DNA where a 3 end is available Second round of replication New leading strand New lagging strand Further rounds of replication Shorter and shorter daughter molecules

Fig µm Staining of telomeres Florescence In Situ Hybridization (FISH) “probe” = (5’-CTAACC-3’) 100

08_Figure37.jpg

Fig. 16-7a Hydrogen bond 3 end 5 end 3.4 nm 0.34 nm 3 end 5 end (b) Partial chemical structure(a) Key features of DNA structure 1 nm

Fig a DNA double helix (2 nm in diameter) Nucleosome (10 nm in diameter) Histones Histone tail H1 DNA, the double helixHistones Nucleosomes, or “beads on a string” (10-nm fiber)

Fig b 30-nm fiber Chromatid (700 nm) LoopsScaffold 300-nm fiber Replicated chromosome (1,400 nm) 30-nm fiber Looped domains (300-nm fiber) Metaphase chromosome

What are genes? DNA How do genes work? Mutant phenotypes Short aristae Black body Cinnabar eyes Vestigial wings Brown eyes

What are genes? DNA How do genes work? Garrod -“Inborn errors of metabolism in man” e.g. Alkaptonuria: presence of alkapton in urine due to lack of enzyme -underappreciated at the time…. A gene specifies the action of an enzyme (The “one-gene, one-enzyme” hypothesis) Beadle and Tatum - Genetic studies in Bread Mold (Neurospora) show that biochemical reactions are controlled by genes

Complete media (contains amino acids, nucleotides, vitamins, etc.) Minimal Media (lacks amino acids, nucleotides, vitamins, etc.) Wild type Neurospora grows on minimal media

Complete media 1.X-rays 2.Set up 1000 multiple single spore cultures (in complete media) A B C wt

Complete media Minimal Media 1.X-rays 2.Set up 1000 multiple single spore cultures (in complete media) 3.Test each for growth on minimal media wt Complete media A B C A B C Min. media

1.X-rays 2.Set up 1000 multiple single spore cultures (in complete media) 3.Test each for growth on minimal media 4.Retest on minimal media plus one component A A A A A A A +His+Leu +Arg +Asp+Glu +Asn A A +Lys +Gln Min. media A A +Trp +Tyr A A +Phe +Gly Min. media A A A +Ser+Thr +Met A +Ile Min. media A +Ala A +Pro Min. media A A +Val +Cys Min. media

Fig. 17-2c CONCLUSION Class I mutants (mutation in gene A) Class II mutants (mutation in gene B) Class III mutants (mutation in gene C) Wild type Precursor Enzyme A Ornithine Enzyme B Citrulline Enzyme C Arginine Gene A Gene B Gene C Multiple enzymes are required for arginine biosynthesis

Fig. 17-2c CONCLUSION Class I mutants (mutation in gene A) Class II mutants (mutation in gene B) Class III mutants (mutation in gene C) Wild type Precursor Enzyme A Ornithine Enzyme B Citrulline Enzyme C Arginine Gene A Gene B Gene C Multiple enzymes are required for arginine biosynthesis If we have an Arg requiring mutant, which gene is affected?

Fig. 17-2b RESULTS Classes of Neurospora crassa Wild type Class I mutantsClass II mutants Class III mutants Minimal medium (MM) (control) MM + ornithine MM + citrulline MM + arginine (control) Condition

Fig. 17-2c CONCLUSION Class I mutants (mutation in gene A) Class II mutants (mutation in gene B) Class III mutants (mutation in gene C) Wild type Precursor Enzyme A Ornithine Enzyme B Citrulline Enzyme C Arginine Gene A Gene B Gene C

RNA Protein DNA Replication TranscriptionTranslation

Fig. 17-3a-1 TRANSCRIPTION DNA mRNA (a) Bacterial cell

Fig. 17-3a-2 (a) Bacterial cell TRANSCRIPTION DNA mRNA TRANSLATION Ribosome Polypeptide

ATGACCATGATTACGGATTCACTGGCCGTCGTTTTACAACGTCGTGACTGGGAAAACCCTGGCGTTACCCAACTTAATCGCCTTGCAGCAC ATCCCCCTTTCGCCAGCTGGCGTAATAGCGAAGAGGCCCGCACCGATCGCCCTTCCCAACAGTTGCGCAGCCTGAATGGCGAATGGCGCTT TGCCTGGTTTCCGGCACCAGAAGCGGTGCCGGAAAGCTGGCTGGAGTGCGATCTTCCTGAGGCCGATACTGTCGTCGTCCCCTCAAACTGG CAGATGCACGGTTACGATGCGCCCATCTACACCAACGTGACCTATCCCATTACGGTCAATCCGCCGTTTGTTCCCACGGAGAATCCGACGG GTTGTTACTCGCTCACATTTAATGTTGATGAAAGCTGGCTACAGGAAGGCCAGACGCGAATTATTTTTGATGGCGTTAACTCGGCGTTTCA TCTGTGGTGCAACGGGCGCTGGGTCGGTTACGGCCAGGACAGTCGTTTGCCGTCTGAATTTGACCTGAGCGCATTTTTACGCGCCGGAGAA AACCGCCTCGCGGTGATGGTGCTGCGCTGGAGTGACGGCAGTTATCTGGAAGATCAGGATATGTGGCGGATGAGCGGCATTTTCCGTGACG TCTCGTTGCTGCATAAACCGACTACACAAATCAGCGATTTCCATGTTGCCACTCGCTTTAATGATGATTTCAGCCGCGCTGTACTGGAGGC TGAAGTTCAGATGTGCGGCGAGTTGCGTGACTACCTACGGGTAACAGTTTCTTTATGGCAGGGTGAAACGCAGGTCGCCAGCGGCACCGCG CCTTTCGGCGGTGAAATTATCGATGAGCGTGGTGGTTATGCCGATCGCGTCACACTACGTCTGAACGTCGAAAACCCGAAACTGTGGAGCG CCGAAATCCCGAATCTCTATCGTGCGGTGGTTGAACTGCACACCGCCGACGGCACGCTGATTGAAGCAGAAGCCTGCGATGTCGGTTTCCG CGAGGTGCGGATTGAAAATGGTCTGCTGCTGCTGAACGGCAAGCCGTTGCTGATTCGAGGCGTTAACCGTCACGAGCATCATCCTCTGCAT GGTCAGGTCATGGATGAGCAGACGATGGTGCAGGATATCCTGCTGATGAAGCAGAACAACTTTAACGCCGTGCGCTGTTCGCATTATCCGA ACCATCCGCTGTGGTACACGCTGTGCGACCGCTACGGCCTGTATGTGGTGGATGAAGCCAATATTGAAACCCACGGCATGGTGCCAATGAA TCGTCTGACCGATGATCCGCGCTGGCTACCGGCGATGAGCGAACGCGTAACGCGAATGGTGCAGCGCGATCGTAATCACCCGAGTGTGATC ATCTGGTCGCTGGGGAATGAATCAGGCCACGGCGCTAATCACGACGCGCTGTATCGCTGGATCAAATCTGTCGATCCTTCCCGCCCGGTGC AGTATGAAGGCGGCGGAGCCGACACCACGGCCACCGATATTATTTGCCCGATGTACGCGCGCGTGGATGAAGACCAGCCCTTCCCGGCTGT GCCGAAATGGTCCATCAAAAAATGGCTTTCGCTACCTGGAGAGACGCGCCCGCTGATCCTTTGCGAATACGCCCACGCGATGGGTAACAGT CTTGGCGGTTTCGCTAAATACTGGCAGGCGTTTCGTCAGTATCCCCGTTTACAGGGCGGCTTCGTCTGGGACTGGGTGGATCAGTCGCTGA TTAAATATGATGAAAACGGCAACCCGTGGTCGGCTTACGGCGGTGATTTTGGCGATACGCCGAACGATCGCCAGTTCTGTATGAACGGTCT GGTCTTTGCCGACCGCACGCCGCATCCAGCGCTGACGGAAGCAAAACACCAGCAGCAGTTTTTCCAGTTCCGTTTATCCGGGCAAACCATC GAAGTGACCAGCGAATACCTGTTCCGTCATAGCGATAACGAGCTCCTGCACTGGATGGTGGCGCTGGATGGTAAGCCGCTGGCAAGCGGTG AAGTGCCTCTGGATGTCGCTCCACAAGGTAAACAGTTGATTGAACTGCCTGAACTACCGCAGCCGGAGAGCGCCGGGCAACTCTGGCTCAC AGTACGCGTAGTGCAACCGAACGCGACCGCATGGTCAGAAGCCGGGCACATCAGCGCCTGGCAGCAGTGGCGTCTGGCGGAAAACCTCAGT GTGACGCTCCCCGCCGCGTCCCACGCCATCCCGCATCTGACCACCAGCGAAATGGATTTTTGCATCGAGCTGGGTAATAAGCGTTGGCAAT TTAACCGCCAGTCAGGCTTTCTTTCACAGATGTGGATTGGCGATAAAAAACAACTGCTGACGCCGCTGCGCGATCAGTTCACCCGTGCACC GCTGGATAACGACATTGGCGTAAGTGAAGCGACCCGCATTGACCCTAACGCCTGGGTCGAACGCTGGAAGGCGGCGGGCCATTACCAGGCC GAAGCAGCGTTGTTGCAGTGCACGGCAGATACACTTGCTGATGCGGTGCTGATTACGACCGCTCACGCGTGGCAGCATCAGGGGAAAACCT TATTTATCAGCCGGAAAACCTACCGGATTGATGGTAGTGGTCAAATGGCGATTACCGTTGATGTTGAAGTGGCGAGCGATACACCGCATCC GGCGCGGATTGGCCTGAACTGCCAGCTGGCGCAGGTAGCAGAGCGGGTAAACTGGCTCGGATTAGGGCCGCAAGAAAACTATCCCGACCGC CTTACTGCCGCCTGTTTTGACCGCTGGGATCTGCCATTGTCAGACATGTATACCCCGTACGTCTTCCCGAGCGAAAACGGTCTGCGCTGCG GGACGCGCGAATTGAATTATGGCCCACACCAGTGGCGCGGCGACTTCCAGTTCAACATCAGCCGCTACAGTCAACAGCAACTGATGGAAAC CAGCCATCGCCATCTGCTGCACGCGGAAGAAGGCACATGGCTGAATATCGACGGTTTCCATATGGGGATTGGTGGCGACGACTCCTGGAGC CCGTCAGTATCGGCGGAATTCCAGCTGAGCGCCGGTCGCTACCATTACCAGTTGGTCTGGTGTCAAAAATAA E. Coli LacZ DNA sequence (1 strand shown) base pairs

AUGACCAUGAUUACGGAUUCACUGGCCGUCGUUUUACAACGUCGUGACUGGGAAAACCCUGGCGUUACCCAACUUAAUCGCCUUGCAGCAC AUCCCCCUUUCGCCAGCUGGCGUAAUAGCGAAGAGGCCCGCACCGAUCGCCCUUCCCAACAGUUGCGCAGCCUGAAUGGCGAAUGGCGCUU UGCCUGGUUUCCGGCACCAGAAGCGGUGCCGGAAAGCUGGCUGGAGUGCGAUCUUCCUGAGGCCGAUACUGUCGUCGUCCCCUCAAACUGG CAGAUGCACGGUUACGAUGCGCCCAUCUACACCAACGUGACCUAUCCCAUUACGGUCAAUCCGCCGUUUGUUCCCACGGAGAAUCCGACGG GUUGUUACUCGCUCACAUUUAAUGUUGAUGAAAGCUGGCUACAGGAAGGCCAGACGCGAAUUAUUUUUGAUGGCGUUAACUCGGCGUUUCA UCUGUGGUGCAACGGGCGCUGGGUCGGUUACGGCCAGGACAGUCGUUUGCCGUCUGAAUUUGACCUGAGCGCAUUUUUACGCGCCGGAGAA AACCGCCUCGCGGUGAUGGUGCUGCGCUGGAGUGACGGCAGUUAUCUGGAAGAUCAGGAUAUGUGGCGGAUGAGCGGCAUUUUCCGUGACG UCUCGUUGCUGCAUAAACCGACUACACAAAUCAGCGAUUUCCAUGUUGCCACUCGCUUUAAUGAUGAUUUCAGCCGCGCUGUACUGGAGGC UGAAGUUCAGAUGUGCGGCGAGUUGCGUGACUACCUACGGGUAACAGUUUCUUUAUGGCAGGGUGAAACGCAGGUCGCCAGCGGCACCGCG CCUUUCGGCGGUGAAAUUAUCGAUGAGCGUGGUGGUUAUGCCGAUCGCGUCACACUACGUCUGAACGUCGAAAACCCGAAACUGUGGAGCG CCGAAAUCCCGAAUCUCUAUCGUGCGGUGGUUGAACUGCACACCGCCGACGGCACGCUGAUUGAAGCAGAAGCCUGCGAUGUCGGUUUCCG CGAGGUGCGGAUUGAAAAUGGUCUGCUGCUGCUGAACGGCAAGCCGUUGCUGAUUCGAGGCGUUAACCGUCACGAGCAUCAUCCUCUGCAU GGUCAGGUCAUGGAUGAGCAGACGAUGGUGCAGGAUAUCCUGCUGAUGAAGCAGAACAACUUUAACGCCGUGCGCUGUUCGCAUUAUCCGA ACCAUCCGCUGUGGUACACGCUGUGCGACCGCUACGGCCUGUAUGUGGUGGAUGAAGCCAAUAUUGAAACCCACGGCAUGGUGCCAAUGAA UCGUCUGACCGAUGAUCCGCGCUGGCUACCGGCGAUGAGCGAACGCGUAACGCGAAUGGUGCAGCGCGAUCGUAAUCACCCGAGUGUGAUC AUCUGGUCGCUGGGGAAUGAAUCAGGCCACGGCGCUAAUCACGACGCGCUGUAUCGCUGGAUCAAAUCUGUCGAUCCUUCCCGCCCGGUGC AGUAUGAAGGCGGCGGAGCCGACACCACGGCCACCGAUAUUAUUUGCCCGAUGUACGCGCGCGUGGAUGAAGACCAGCCCUUCCCGGCUGU GCCGAAAUGGUCCAUCAAAAAAUGGCUUUCGCUACCUGGAGAGACGCGCCCGCUGAUCCUUUGCGAAUACGCCCACGCGAUGGGUAACAGU CUUGGCGGUUUCGCUAAAUACUGGCAGGCGUUUCGUCAGUAUCCCCGUUUACAGGGCGGCUUCGUCUGGGACUGGGUGGAUCAGUCGCUGA UUAAAUAUGAUGAAAACGGCAACCCGUGGUCGGCUUACGGCGGUGAUUUUGGCGAUACGCCGAACGAUCGCCAGUUCUGUAUGAACGGUCU GGUCUUUGCCGACCGCACGCCGCAUCCAGCGCUGACGGAAGCAAAACACCAGCAGCAGUUUUUCCAGUUCCGUUUAUCCGGGCAAACCAUC GAAGUGACCAGCGAAUACCUGUUCCGUCAUAGCGAUAACGAGCUCCUGCACUGGAUGGUGGCGCUGGAUGGUAAGCCGCUGGCAAGCGGUG AAGUGCCUCUGGAUGUCGCUCCACAAGGUAAACAGUUGAUUGAACUGCCUGAACUACCGCAGCCGGAGAGCGCCGGGCAACUCUGGCUCAC AGUACGCGUAGUGCAACCGAACGCGACCGCAUGGUCAGAAGCCGGGCACAUCAGCGCCUGGCAGCAGUGGCGUCUGGCGGAAAACCUCAGU GUGACGCUCCCCGCCGCGUCCCACGCCAUCCCGCAUCUGACCACCAGCGAAAUGGAUUUUUGCAUCGAGCUGGGUAAUAAGCGUUGGCAAU UUAACCGCCAGUCAGGCUUUCUUUCACAGAUGUGGAUUGGCGAUAAAAAACAACUGCUGACGCCGCUGCGCGAUCAGUUCACCCGUGCACC GCUGGAUAACGACAUUGGCGUAAGUGAAGCGACCCGCAUUGACCCUAACGCCUGGGUCGAACGCUGGAAGGCGGCGGGCCAUUACCAGGCC GAAGCAGCGUUGUUGCAGUGCACGGCAGAUACACUUGCUGAUGCGGUGCUGAUUACGACCGCUCACGCGUGGCAGCAUCAGGGGAAAACCU UAUUUAUCAGCCGGAAAACCUACCGGAUUGAUGGUAGUGGUCAAAUGGCGAUUACCGUUGAUGUUGAAGUGGCGAGCGAUACACCGCAUCC GGCGCGGAUUGGCCUGAACUGCCAGCUGGCGCAGGUAGCAGAGCGGGUAAACUGGCUCGGAUUAGGGCCGCAAGAAAACUAUCCCGACCGC CUUACUGCCGCCUGUUUUGACCGCUGGGAUCUGCCAUUGUCAGACAUGUAUACCCCGUACGUCUUCCCGAGCGAAAACGGUCUGCGCUGCG GGACGCGCGAAUUGAAUUAUGGCCCACACCAGUGGCGCGGCGACUUCCAGUUCAACAUCAGCCGCUACAGUCAACAGCAACUGAUGGAAAC CAGCCAUCGCCAUCUGCUGCACGCGGAAGAAGGCACAUGGCUGAAUAUCGACGGUUUCCAUAUGGGGAUUGGUGGCGACGACUCCUGGAGC CCGUCAGUAUCGGCGGAAUUCCAGCUGAGCGCCGGUCGCUACCAUUACCAGUUGGUCUGGUGUCAAAAAUAA E. Coli LacZ RNA sequence nucleotides

MTMITDSLAVVLQRRDWENPGVTQLNRLAAHPPFASWRNSEEARTDRPSQQLRSLNGEWRFAWFPAPEAVPESWLECDLPEADTVVVPSNW QMHGYDAPIYTNVTYPITVNPPFVPTENPTGCYSLTFNVDESWLQEGQTRIIFDGVNSAFHLWCNGRWVGYGQDSRLPSEFDLSAFLRAGE NRLAVMVLRWSDGSYLEDQDMWRMSGIFRDVSLLHKPTTQISDFHVATRFNDDFSRAVLEAEVQMCGELRDYLRVTVSLWQGETQVASGTA PFGGEIIDERGGYADRVTLRLNVENPKLWSAEIPNLYRAVVELHTADGTLIEAEACDVGFREVRIENGLLLLNGKPLLIRGVNRHEHHPLH GQVMDEQTMVQDILLMKQNNFNAVRCSHYPNHPLWYTLCDRYGLYVVDEANIETHGMVPMNRLTDDPRWLPAMSERVTRMVQRDRNHPSVI IWSLGNESGHGANHDALYRWIKSVDPSRPVQYEGGGADTTATDIICPMYARVDEDQPFPAVPKWSIKKWLSLPGETRPLILCEYAHAMGNS LGGFAKYWQAFRQYPRLQGGFVWDWVDQSLIKYDENGNPWSAYGGDFGDTPNDRQFCMNGLVFADRTPHPALTEAKHQQQFFQFRLSGQTI EVTSEYLFRHSDNELLHWMVALDGKPLASGEVPLDVAPQGKQLIELPELPQPESAGQLWLTVRVVQPNATAWSEAGHISAWQQWRLAENLS VTLPAASHAIPHLTTSEMDFCIELGNKRWQFNRQSGFLSQMWIGDKKQLLTPLRDQFTRAPLDNDIGVSEATRIDPNAWVERWKAAGHYQA EAALLQCTADTLADAVLITTAHAWQHQGKTLFISRKTYRIDGSGQMAITVDVEVASDTPHPARIGLNCQLAQVAERVNWLGLGPQENYPDR LTAACFDRWDLPLSDMYTPYVFPSENGLRCGTRELNYGPHQWRGDFQFNISRYSQQQLMETSHRHLLHAEEGTWLNIDGFHMGIGGDDSWS PSVSAEFQLSAGRYHYQLVWCQK E. Coli LacZ protein sequence – 1024 amino acids

Fig Second mRNA base First mRNA base (5 end of codon) Third mRNA base (3 end of codon)

Beta-galactosidase protein (E. coli)LacZ (Beta-galactosidase) gene (DNA) LacZ mRNA

ATGAAATTTACCGTAGAACGTGAGCATTTATTAAAACCGCTACAACAGGTGAGCGGTCCGTTAGGTGGTCGTCCTACGCTA CCGATTCTCGGTAATCTGCTGTTACAGGTTGCTGACGGTACGTTGTCGCTGACCGGTACTGATCTCGAGATGGAAATGGTG GCACGTGTTGCGCTGGTTCAGCCACACGAGCCAGGAGCGACGACCGTTCCGGCGCGCAAATTCTTTGATATCTGCCGTGGT CTGCCTGAAGGCGCGGAAATTGCCGTGCAGCTGGAAGGTGAACGGATGCTGGTACGCTCCGGGCGTAGCCGTTTTTCGCTG TCTACCCTGCCAGCGGCGGATTTCCCGAACCTCGATGACTGGCAGAGTGAAGTCGAATTTACCCTGCCGCAGGCAACGATG AAGCGTCTGATTGAAGCGACCCAGTTTTCTATGGCGCATCAGGACGTTCGCTATTACTTAAATGGTATGCTGTTTGAAACC GAAGGTGAAGAACTGCGCACCGTGGCAACCGACGGCCACCGTCTGGCGGTCTGTTCAATGCCAATTGGTCAATCTTTGCCA AGCCATTCGGTGATCGTACCGCGTAAAGGCGTGATTGAACTGATGCGTATGCTCGACGGCGGCGACAATCCGCTGCGCGTA CAGATTGGCAGCAACAACATTCGCGCCCACGTTGGCGACTTTATCTTCACCTCCAAACTGGTGGATGGTCGCTTCCCGGAT TATCGCCGCGTTCTGCCGAAGAACCCGGACAAACATCTGGAAGCTGGCTGCGATCTGCTCAAGCAGGCGTTTGCTCGCGCG GCGATTCTCTCTAACGAGAAATTCCGCGGCGTACGTCTTTATGTCAGCGAAAACCAGCTGAAAATCACCGCCAACAACCCG GAACAGGAAGAAGCGGAAGAGATCCTCGACGTTACCTATAGCGGTGCGGAGATGGAAATCGGCTTCAACGTCAGTTATGTG CTGGATGTTCTGAACGCGCTGAAATGCGAAAACGTCCGCATGATGCTGACCGATTCGGTTTCCAGCGTGCAGATTGAAGAT GCGGCCAGCCAGAGCGCGGCTTATGTTGTCATGCCAATGAGACTGTAA E. Coli Sliding Clamp DNA sequence (1 strand shown) base pairs E. Coli Sliding Clamp Protein sequence- 366 amino acids MKFTVEREHLLKPLQQVSGPLGGRPTLPILGNLLLQVADGTLSLTGTDLEMEMVARVALVQPHEPGATTVPARKFFDICRGLPEGAEIAVQLE GERMLVRSGRSRFSLSTLPAADFPNLDDWQSEVEFTLPQATMKRLIEATQFSMAHQDVRYYLNGMLFETEGEELRTVATDGHRLAVCSMPI GQSLPSHSVIVPRKGVIELMRMLDGGDNPLRVQIGSNNIRAHVGDFIFTSKLVDGRFPDYRRVLPKNPDKHLEAGCDLLKQAFARAAILSNEK FRGVRLYVSENQLKITANNPEQEEAEEILDVTYSGAEMEIGFNVSYVLDVLNALKCENVRMMLTDSVSSVQIEDAASQSAAYVVMPMRL

Fig b Origin of replication RNA primer “Sliding clamp” DNA pol III Parental DNA

Sliding clamp protein (E. coli)- shown with DNA double helix

Fig DNA molecule Gene 1 Gene 2 Gene 3 DNA template strand TRANSCRIPTION TRANSLATION mRNA Protein Codon Amino acid

Fig. 5-27c-2 Ribose (in RNA)Deoxyribose (in DNA) Sugars (c) Nucleoside components: sugars

Fig. 5-27c-1 (c) Nucleoside components: nitrogenous bases Purines Guanine (G) Adenine (A) Cytosine (C) Thymine (T, in DNA)Uracil (U, in RNA) Nitrogenous bases Pyrimidines

Fig Sugar–phosphate backbone 5 end Nitrogenous bases Thymine (T) Adenine (A) Cytosine (C) Guanine (G) DNA nucleotide Sugar (deoxyribose) 3 end Phosphate Chemical structure of DNA

Fig Sugar–phosphate backbone 5 end Nitrogenous bases Thymine (T) Adenine (A) Cytosine (C) Guanine (G) DNA nucleotide Sugar (deoxyribose) 3 end Phosphate Uracil (U) OH RNA Chemical structure of RNA -ribose instead of deoxyribose Uracil instead of thymine Cytosine (C)

RNA Protein DNA Replication TranscriptionTranslation Polymerase Monomers DNA Pol III (and I) dNTPs Direction of synthesis 5’ to 3’ TemplatessDNA Product polynucleotid e

RNA Protein DNA Replication TranscriptionTranslation Polymerase Monomers DNA Pol III (and I) RNA Pol dNTPsNTPs Direction of synthesis 5’ to 3’ TemplatessDNA Product polynucleotid e

Fig. 17-7a-1 Promoter Transcription unit DNA Start point RNA polymerase

Fig. 17-7a-2 Promoter Transcription unit DNA Start point RNA polymerase Initiation RNA transcript 5 5 Unwound DNA Template strand of DNA

Fig. 17-7a-3 Promoter Transcription unit DNA Start point RNA polymerase Initiation RNA transcript 5 5 Unwound DNA Template strand of DNA 2 Elongation Rewound DNA RNA transcript

Fig. 17-7a-4 Promoter Transcription unit DNA Start point RNA polymerase Initiation RNA transcript 5 5 Unwound DNA Template strand of DNA 2 Elongation Rewound DNA RNA transcript 3 Termination Completed RNA transcript

Fig. 17-7b Elongation RNA polymerase Nontemplate strand of DNA RNA nucleotides 3' end Direction of transcription (“downstream”) Template strand of DNA Newly made RNA 3' 5'

Fig A eukaryotic promoter includes a TATA box Promoter TATA box Start point Template DNA strand Transcription factors Several transcription factors must bind to the DNA before RNA polymerase II can do so Additional transcription factors bind to the DNA along with RNA polymerase II, forming the transcription initiation complex. RNA polymerase II Transcription factors RNA transcript Transcription initiation complex

RNA Protein DNA Replication TranscriptionTranslation Polymerase Monomers DNA Pol III (and I) RNA Pol dNTPsNTPs Direction of synthesis 5’ to 3’ TemplatessDNA Product polynucleotid e