Download Nucleic Acids

Nucleic Acids
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DNA: deoxyribonucleic acid; found in cells (except for rbc); contain genetic information in segments called genes;
DNA is a “blueprint” for an organism. One gene codes for one protein.
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RNA: ribonucleic acid; also found in cells (except for rbc); responsible for transmitting and expressing the
genetic information of DNA by translating DNA into proteins. The proteins are the “doers”.
Structure of Nucleic Acids:
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Nucleoside:
– A 5 membered cyclic sugar unit + cyclic nitrogen containing base (pyrimidine and purine bases)
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Nucleotide:
– A 5 membered cyclic sugar unit + cyclic nitrogen containing base + phosphate (a nucleoside and phosphate
unit linked via a phosphate ester bond)
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Nucleic Acids
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Naming nucleosides:
– Prefix deoxy- if sugar is deoxyribose
– No prefix if sugar is ribose
– Base name –ending, +osine (for purines)
– Base name –ending, +idine (for pyrimidines)
Naming nucleotides:
– Name nucleoside + monophosphate, diphosphate or triphosphate
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Nucleic Acids
• Polynucleotides: The –OH of C-3 forms a phosphate diester linkage with the phosphate of C-5. The free
phosphate group is the 5’ end; the free –OH group is the 3’ end.
• Just as the amino acid order is important in proteins, the order of the nucleotides in nucleic acids is significant; 3’
TAG 5’ is not the same as 3’ GAT 5’!
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