THE STRUCTURE OF DNA PART 2

Watson and Crick Tell me about the discovery made by

Watson and Crick. These scientists made even more

important discoveries.

Yesterday’s Activity What observations did you make about

DNA during yesterday’s activity?

What about Purines and Pyrimidines?

Watson and Crick When they figured out that DNA has a

double helix structure, they also made a connection with how the nucleotide base pairs match up.

Look at these two base pairs Is Adenine a purine or pyrimidine? What about Thymine?

So, Purines pair with Pyrimidines! Watson and Crick realized this when they

came up with the double helix structure. This was because of the hydrogen bonds between the two matched up perfectly to create the double helix structure.

Hydrogen Bonds

Ok, Let’s Review Before a Quiz! Who was Gregor Mendel? Who was Frederick Griffith? Who was Oswald Avery? Who were Hershey and Chase? Who was Chargaff? Who was Franklin? Who were Watson and Crick?

DNA review What makes up the backbone of DNA? What are the 4 nucleotides? What is Chargaff’s Rule? What is the difference between a purine

and a pyrimidine? What bond holds together the two

strands of DNA?