MIC 205 1st Edition Lecture 13 Outline of Last LectureI. Controling Microbial Growth Cont.a. Biofilms II. Microbial GeneticsOutline of Current Lecture III. DNA ReplicationIV. DNA TranscriptionV. Translation of mRNACurrent Lecture DNA Replication- Anabolic polymerization process- Begin with double stranded parental DNA helix- Split into two daughter strands with a complementary new strando Three key concepts1. Replication is semiconservative- One parental one daughter strand2. Replication requires a step-wise process- Remove DNA associated proteins, helicase, synthesize RNA primers (starting blocks for synthesis), DNA polymerase III extendsthe primers, degrade RNA primers and fill in gaps with DNA polymerase I, and rewind new strands. 3. DNA polymerase III synthesizes new DNA strands in only ONE direction (5’to 3’)- Strands are antiparallel so synthesized differentlyo Leading strand continuous synthesis towards the forko Lagging strand is away from the fork and discontinuous- Replication of Circular Chromosomes (prokaryotes)o Bidirectional replication- replicates around both sideso Origin of replication- place where replication beginsThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.- Start rounds of replication before the prior is doneo Topoisomerase relieves stress on bacteria Transcription- Copy DNA into RNA sequences- RNA transcripts mRNA—temp carrier of info from chromosomes to ribosomes rRNA-- ribosome tRNA—move amino acids to ribosomes in protein synthesis- 3 steps1. Initiation: sigma factor with RNA polymerase recognizes and binds to promoter sequence on DNA template 2. Elongation: RNA polymerase extends the new transcript using triophosphate ribonucleotides (making RNA with DNA template)3. Termination: RNA polymerase detaches and releases transcript upon reachingthe terminator sequence on the DNA template- DNA Polymerase vs. RNA Polymerase- Transcription vs. ReplicationTranslation of mRNA- Synthesis of protein through “interpreting” the RNA nucleotide sequence- Carried out by ribosomes in cytosol- Bacterial mRNA can code for several proteinso Start codons and stop codons Start is always AUG- Codons are clusters of mRNA (3 nucleotides) that code for special amino
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