BIO 325 Lecture 4: Deoxyribose Nucleic Acid
Deoxyribose Nucleic Acid (DNA)
• DNA contains
o Phosphate
o Pentose sugar: deoriose = H at ’ aro; riose = OH at ’ aro
o Nitrogenous base: Adenine (A), Guanine (G), Cytosine (C), Thymine (T)
• NucleoSIDES – pentose sugar and nitrogenous base
• NucleoTIDES – nucleoside; pentose sugar, nitrogenous base, and phosphate
o Purines – bases with a DOUBLE RING structure (A, G)
o Pyrimidines – bases with a SINGLE RING structure (C, T)
o DNA = A + T, G + C by hydrogen bond
o Chemical structure of DNA provides directionality of 5’ Phosphor -> ’ OH
• Sigle strads of DNA hae ’ ad 5’ ed
• Two strands of the double helix are antiparallel
2 Types of Bonds Create DNA
• Phosphodiester Bonds – connect the nucleotides together in a single strand
• Hydrogen Bonds – connect the complementary strands together
o G-C pairings make 3 hydrogen bonds
o A-T pairings make 2 hydrogen bonds
4 Requirements for DNA to be Genetic Material
• Replicate with little errors, be able to change with mutations and variations, store
information, transmit information
o Must replicate – DNA replication
o Must allow for information to change – mutation and recombination
o Must carry information – cracking the genetic code
o Must govern the expression of the phenotype – gene function
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