DNA Interactive
Use the internet site below to answer the following questions. Use heading below to navigate the site and answer the questions in your notebook. Enjoy your journey.
http://www.dnai.org/a/index.html
Finding the Structure:
Finding the Structure – Pieces of the puzzle – Pauling’s Triple Helix
What was the problem with Linus Pauling’s triple helix?
Finding the Structure – Pieces of the puzzle – Franklin’s X-ray
What data, besides the fact that DNA was a helix, did Watson and Crick obtain from Franklin’s X-ray?
Finding the Structure – Pieces of the puzzle - Watson Base Pairing
What did Watson learn from his cardboard cutouts?
Finding the Structure – Putting it together -Base Pairing Interactive
Orient the base pairs to show the correct bonding.
Draw the bases, showing the atoms and the bonds.
Copying the Code
Copying the Code -Pieces of the puzzle – Model of DNA Replication:
After the DNA structure was found, there were three models considered possible models for replication. Draw a parent strand below. Then draw the replicated strands from each model. Be sure to use different colors or inks.
Copying the Code -Pieces of the puzzle – Semi conservative Replication
The experiment by Matt Meselson and Frank Stahl showed that DNA is replicated semi-conservatively. This experiment is often referred to as “the most beautiful experiment in molecular biology.” (DNAi.org) Describe the experiment and how the data supports a semi-conservative model.
Copying the Code -Pieces of the puzzle – DNA Synthesis
Who isolated the enzyme, DNA Polymerase?
What is the role of DNA Polymerase? Describe how each of the variables in the test tube affects the results of replication. (Example – not all nucleotides present, digesting DNA)
Copying the Code -Putting it together – Replication
What is the role of Helicase? How fast can it spin DNA?
Why is only one strand copied continuously and not the other?
Why does the other fragment need to loop? What are these fragments called?