My advice on the matters for the day (as listed in the calendar):
DNA
- DNA Replication: Many people consider this section review, but you might find some surprises in the notes on DNA replication (new version dated Sep 27, 2017). Addressing Study Questions 1, 3, and 4 might help you gauge if you know what you're talking about
- Meselson & Stahl (1958): Many people have learned of this experiment in previous classes. They say "I already know that DNA replicates semiconservatively", but few really understand how the experiment that tests that assertion works, and that's what's important. Today is your chance. Do what you need to do to understand the experiment or, failing that, to develop questions that will lead you to understanding. The companion to the article (new version dated Sep 27, 2017) and its study questions may help, particularly Study Questions 2, 7, 9, and 14.
- Problem Set 4: Some are surprised by their inability to apply what they thought they knew. Problem Set 4, Problem 8, gives you the opportunity to apply what you should know about DNA replication in a practical way. We'll work on this problem in class, but before class, make sure that you are familiar with the Polymerase Chain Reaction, perhaps using the links given in Problem 4.8. tutorial
I. Basic Information
- Your name
II. Old business
(no need to repeat anything you've said in a previous questionnaire)
- DNA Structure
Anything further you'd like to discuss regarding
the notes
DNA Structure?
OK with the nature of palindromes? Problem Set 4, problem 2?
- How to read a research article
Anything further you'd like to discuss regarding
the mini-article
(describing an experiment concerning DNA replication) and the
suggestions how to go about
reading it (and any research article)?
III. DNA replication
A. How far have you gotten in the part 1 of the notes entitled
DNA Replication, Part I?
B. Consider how comfortable you are with the following topics regarding DNA replication:
- The need for a pre-existing 3'-OH end, generally an RNA primer
- The concepts of leading and lagging strands
- The requirement that DNA synthesis always proceeds 5' to 3'
- Proofreading and accuracy
IV. Meselson and Stahl
- How far have you gotten in Meselson and Stahl (1958) and its
companion?
- Consider how comfortable you are with the following topics regarding Meselson & Stahl:
- The topological problem implicit in the replication model presented by Watson and Crick
- Dispersive replication, and how it addresses the topological problem
- The critical differences between the three featured models of DNA replication
- How heavy isotopes can distinguish new from old DNA
- What properties of cesium chloride are helpful in this procedure
- Equilibrium density centrifugation
- How to read Fig. 4 (e.g. what do position and ultraviolet absorption indicate)
- The relationship between Meselson and Stahl's results and the predictions of the three featured replication models
- How Delbrück's topological problem was ultimately resolved
Please relate your thoughts
V. Miscellaneous
Any other comments, questions, suggestions, or concerns you may have?
Thanks!
REMEMBER TO CLICK SUBMIT!
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