BIOLOGY GENETICS COMPLETE STUDY GUIDE 2026 MIDTERM

DNA Structure:

● DNA is double stranded - which makes it 50x as strong as a single strand

● DNA is made up of building blocks called nucleotides - have one deoxyribose sugar, one

phosphate group, and one nitrogenous base

â—‹ Nitrogenous bases = the information carrying part of DNA

â–  A and G = purines b/c they have two ring structure

â–  C and G = pyrimidines b/c they have single ring structure

â–  Because purines always pair with pyrmidines, the double helix has the

same width throughout

â–  A and T are bonded by two hydrogen bonds, G and C are bonded by three

is provided by hydrogen bonding); hydrogen,