DNA Structure

Watson, Crick and Franklin

DNA Structure 3 main components: –Deoxyribose sugar –Phosphate group –Nitrogenous base Antiparallel strands

DNA Structure Hydrogen bonds between bases. Arranged in a double helix

2 H bonds 3 H bonds

Bonding Phosphodiester bonds join sugar and phosphate groups Glycosyl bonds join nitrogenous bases to sugars

Nitrogenous Bases Pyrimidines Purines T GA C

Chargaff’s Rule Amount of A equals that of T (A=T) Amount of C equals that of G (C=G) A purine always pairs with a pyrimidine (complementary base pairing) –A pairs with T –C pairs with G

Complementary Base Pairing If you know the sequence of one strand, you can find the sequence of the complementary strand 5’ ATGCCGTA 3’ 3’ TACGGCAT 5’

Some Researchers to Know Friedrich Miescher Frederick Griffith Joachim Hammerling Erwin Chargaff Alfred Hershey & Martha Chase Rosalind Franklin James Watson & Francis Crick