From Gene to Protein: A Historical Perspective "The Watson & Crick Model of DNA"

Read the original article "A Structure for Dexoxyribonucleic Acid".  Mark up the text, this is a difficult journal article to get through.  Stop as you are reading.  Talk with another classmate.  Use these questions to help get to the meaning of the article.

Click here for information about Linus Pauling's hypothesis about the structure of DNA

1. Describe the structure of DNA monomers by using citations from the article. How is the structure arranged, that is, which of the “parts” are on the outside? Which ones are on the inside of the molecule? Cite the article.

2. How did Linus Pauling’s model differ from Watson and Crick’s model for DNA? Explain in detail.

3. What type of bond holds the bases together? Cite the article. From what we have talked about this year regarding this bond, how might this bond affect the overall stability of the DNA molecule?

4. In the eighth paragraph, a very important observation is made about base pairing. What is the significance of how bases pair up?

5. Reread the last half of the article. Based on what Watson and Crick say, try to hypothesize what their “possible copying mechanism” might be. Use clues from the article in your explanation.

Watch "The Secret of Photo 51" about Rosalind Franklin's research and contribution to the discovery of the structure and function of DNA.

Your summary can be done in pairs and will be submitted to Canvas.

From Gene to Protein: A Historical Perspective Protein vs. DNA

How did scientists discover the source of heritable genetic information?

Before we begin the discussion, let's review the structure of proteins.
Watch the video from education portal about the four levels of protein structure

Why might Rosalind Franklin's X-ray diffraction photograph have been interpreted as an alpha secondary structure?

Griffith's experiments (1928)
Go through the animation in Concept 17 (A Gene is Made from DNA) at DNA from the Beginning (dnaftb.org)
How did Griffith's discoveries help identify the source of genetic information?  Why were Griffith's "transforming factors" different from proteins?

Hershey-Chase Experiments (1952)
The results of Griffith's experiments began a quest among scientists to identify his "transforming factor". 
Watch the animation on the Hershey-Chase Experiment
What are the elements that make up a nucleic acid vs. a protein?
Why did Hershey and Chase use radioactive sulfer and phosphorus in their experiments?
Is DNA or protein the genetic material of a phage T2?
What evidence does this experiment give you to support this idea?
DNA Extraction 
How can DNA, a submicroscopic molecule, be visualized by the naked eye?
What must be done to extract and isolate DNA from human cheek cells?
What can we conclude about the chemical nature of DNA through isolation techniques?

Materials provided:
centrifuge tubes, disposable cups, sports drink, ethyl acohol, pipettes, cell lysis (detergent) solution, meat tenderizer (enzyme)

How will you use the above materials to extract DNA from your cheek cells?

More information in newborn genetic screening

Video from the lecture that started to watch on Wednesday. Take the time to watch the remainder of it to help in your research for your policy.

Genetic Disorder Task Force

You are going to get into new large groups (of 6 total students), and select a role based on the link below (it has all of the information needed). Your job in the task force is to create a new policy for genetic testing and to create a way to get the information out to the public.  We will also be having a debate/discussion about these topics before spring break.
Click here for the packet of information on the assignment.

Block day week of 2/10

Go over whiteboards of written responses for take-home quiz.

Work on water lab & dialysis tubing lab.  Modified water lab (without part 6) is due by Thursday Feb 13.

Friday work day

Today we started to whiteboard the constructed response answers to the BioChem take home quiz.  The quiz is due next week on the block day, we will discuss answers to the constructed response on the block day.

The water lab is up on the canvas site.  It is due by next Thursday Feb 13.  If it is turned in by that day, you will be eligible to receive full credit (even if you have to fix it).  If it is late, the highest grade you can receive for that assignment is a C. 

Diffusion across a Selectively permeable membrane

New lab all about diffusion of molecules and how it all works! 

Click here for directions -- again, create a google doc, share it with your group, to collect data and upload to canvas.