BCHM 4116 1st Edition Lecture 14Outline of Last Lecture I. DNA replication Outline of Current Lecture I. DNA replication Current Lecture1. How is DNA Replicated? a. Semiconservativei. 1 of 2 original strands are conserved in each of the 2 progeny b. Bidirectionali. Begins at 1 or more specific region called origin of replication ii. Involves 2 replication forks that move in opposite directions c. Semi-discontinuous i. Continuous strand = Leading strand ii. Discontinuous strand = Lagging strand via Okazaki fragments iii.d. Replication:i. DNA gyrase1. Type II topoisomerase2. Overcome torsional stress imposed upon unwinding by introducing negative supercoils ii. Helicase1. Unwinds 2. Disrupt hydrogen bonds iii. Single-stranded DNA binding proteins 1. Binds to single strands to prevent from re-annealing iv. DNA Polymerase1. Uses ssDNA as template2. Synthesize DNA only in 5’3’ v. DNA Pol I 1. Only Pol with 5’3’ exonuclease, meaning it can replace RNA primer with DNA vi. DNA ligase1. Seals remaining nicks in Okazaki fragments vii. Ter Region1. DNA replication terminates @ TerThese 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.2. Termination requires binding of Tusprotein toTera. Tus is a counterhelicasei. Tus prevents DNA duplex from unwinding by blocking progression of replication
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