DNA Structure

Fredrick Griffith

Made scientists interested in studying DNA through his experiments in 1928.

Oswald Avery

Discovered that DNA is the molecule responsible for the transfer of genetic material in 1944.

Martha Hershey & Alfred Chase

Confirmed that DNA is definitely the genetic material in 1952.

Edwin Chargaff

Discovered that the amount of adenine = the amount of thymine, and the amount of cytosine = the amount of guanine in 1950.

Roslind Franklin

Used x-ray diffraction to get an image structure of DNA in 1951.

James Watson & Francis Crick

Used Chargaff & Franklin’s work to determine the structure of DNA, and built the first double helix model in 1953.

What are the 3 things that DNA does?

Stores and copies hereditary information, and transmits hereditary information to future generations.

Which macromolecule makes up DNA?

Nucleic Acid.

What are the building blocks of nucleic acids? What are the 3 things that make up these building blocks?

Nucleotides = building blocks of nucleic acids. Sugar (deoxyribose), a phosphate, and 4 nitrogenous bases make up the building blocks.

What type of bonds hold the phosphate and sugar backbones of DNA in place?

Covalent (strong) Bonds.

What type of bonds hold the nitrogenous bases of DNA in place?

Hydrogen (weak) Bonds.

What does Chargaff’s Rule say?

C=G and T=A

Which bases are pyrimidines?

Thymine and Cytosine = 1 carbon ring bases.

Which bases are purines?

Adenine and Guanine = 2 carbon ring bases.

Describe what it means when people say, “DNA is a double helix”

DNA is like a twisted ladder. The sides of the ladder is made of a sugar and a phosphate, and the sides of the ladder is made out of the 4 nitrogenous bases.