The Blueprint of Life: DNA to Protein. What is genetics? DNA Structure 4/27/2011. Chapter 7

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1 The Blueprint of Life: NA to Protein Chapter 7 What is genetics? The science of heredity; includes the study of genes, how they carry information, how they are replicated, how they are expressed NA Structure 1

2 NA Structure NA Structure NA Structure 2

3 and the Central ogma : nucleotides are added to the 3 position (OH group) 3

4 Original New New Original 4

5 T C A G A C G G A T A G C A C T G A T 3 L R T C A G A C G G A T A G C A C T G A T 3 L R T C A G A C G G A T A G C A C T G A T 3 L R 5

6 T C A G A C G G A T A G C A C T G A T 3 L R T C A G A C G G A T A G C A C T G A T 3 L R T C A G A C G G A T A G C A C T G A T 3 and so on L R 6

7 NA replication a closer look The replication fork (shown in Figure 7.6) 3 The replication fork 7

8 3 The replication fork 3 The replication fork 3 The replication fork 8

9 3 The replication fork Leading strand - continuous synthesis Lagging strand - discontinuous synthesis (Okazaki fragments) 9

10 How does a cell that takes 40 minutes to replicate the chromosome divide every 20 minutes? Transcription Gene Expression Translation 10

11 Gene expression Replication vs Transcription Gene expression RNA is transcribed from NA 11

12 Replication vs Transcription T C A G A C G G A T A G C A C T G A T 3 NA polymerase vs. RNA polymerase (no primer needed) eoxyribonucleotides vs. ribonuceotides Replication vs Transcription T C A G A C G G A T A G C A C T G A T 3 NA polymerase vs. RNA polymerase (no primer needed) eoxyribonucleotides vs. ribonuceotides Thymine vs. uracil Replication vs Transcription T C A G A C G G A U A G C A C T G A T 3 NA polymerase vs. RNA polymerase (no primer needed) eoxyribonucleotides vs. ribonuceotides Thymine vs. uracil 12

13 Replication vs Transcription T C A G A C G G A U A G C A C T G A T 3 NA polymerase vs. RNA polymerase (no primer needed) eoxyribonucleotides vs. ribonuceotides Thymine vs. uracil Replication vs Transcription T C A G A C G G A U A G C A C T G A T 3 NA polymerase vs. RNA polymerase (no primer needed) eoxyribonucleotides vs. ribonuceotides Thymine vs. uracil Replication vs Transcription T C A G A C G G A U A G C A C T G A T 3 and so on NA polymerase vs. RNA polymerase (no primer needed) eoxyribonucleotides vs. ribonuceotides Thymine vs. uracil 13

14 Transcription: NA to RNA Requires an enzyme.. RNA nucleotides Base pairing rules for building RNA from a NA template Process proceeds in the direction --->3 Process begins at the promoter region and ends at the terminator sequence Promoter Orients RNA Polymerase Promoter Orients RNA Polymerase Transcription initiates at a promoter (sequence theme recognized by RNA polymerase) Transcription stops at a terminator 14

15 Promoter Orients RNA Polymerase Initiation - RNA polymerase binds to promoter (guided by sigma factor) Elongation - RNA polymerase synthesizes RNA in 3 (no primer needed) RNA synthesis Initiation - RNA polymerase binds to promoter (guided by sigma factor) Elongation - RNA polymerase synthesizes RNA in 3 (no primer needed) Termination - RNA synthesis Initiation - RNA polymerase binds to promoter (guided by sigma factor) Elongation - RNA polymerase synthesizes RNA in 3 (no primer needed) Termination - Terms to note: Monocistronic Polycistronic (prokaryotes only) Upstream ownstream 15

16 Summary Summary Bacterial Gene Expression - Transcription 16

17 What are the possible products from transcription? Messenger RNA (mrna) Transfer RNA (trna) Ribosomal RNA (rrna) Quick check.. o we have a protein yet? What have we made? What is next? Gene Expression - Overview Transcription Translation Coded by NA: RNA transcripts: Protein molecules Protein A Protein B Protein C Protein Protein E Protein F Protein G Protein H Protein I Protein Protein Protein Protein Protein Protein Protein Protein Protein Protein 17

18 Gene Expression - Overview 18