Building Structural Model of DNA

Question 1

What was discovered about DNA in the late 1940’s

Answer 1

DNA is a polymer of nucleotides. It consists of deoxyribose sugar, nitrogenous base and a phosphate group.

Question 2

Deoxyribose sugar is a …

Answer 2

5 carbon sugar.

Question 3

What did Chargraff analyze that contributed to molecular diversity?

Answer 3

Analyzed and figured out the base composition of DNA among various species is not equal. This made molecular diversity a more credible candidate for genetic material.

Question 4

What is Chargraffs Rule?

Answer 4

1.) Adenine is in equal amounts to Thymine
2.) Cytosine is in equal amounts to Guanine
3.) The constant distance is 3 rings between the sugar phosphate backbones, as purines are always joined with pyrimidines making it a double ring + single ring.

Question 5

What did Rosalind Franklin discover?

Answer 5

• Produced an xray diffraction of DNA and was able to prove that DNA was a spiral helix.
• Based on how DNA reacted to water, she concluded that nitrogenous bases were located INSIDE the helical structure and the sugar phosphate backbone was located on the OUTSIDE of the helical structure.

Question 6

What happened in 1953?

Answer 6

Watson and Crick stole Franklins xray and concluded that DNA is a double helix model.