Nucleic Acid
Structure & Function
Functions of Nucleotides and Nucleic Acids
• Nucleic acids are polymers of nucleotides used for:
– storage of genetic info (DNA)
– transmission of genetic info (mRNA)
– processing of genetic information (ribozymes)
– protein synthesis (tRNA and rRNA)
• Nucleotides are also used in the monomer form for cellular
functions:
– energy for metabolism (ATP)
– enzyme cofactors (NAD+, NADP+, FAD, FMN, Coenzyme A)
– signal transduction (cAMP)
– intermediates in biosynthetic reactions (UDP-glucose , SAM)
Nucleotides and Nucleosides
• Nucleotide =
– nitrogeneous base
– pentose
– phosphate
• Nucleoside =
– nitrogeneous base
– pentose
• Carbon AND nitrogen atoms on the nitrogenous base are numbered in
cyclic format.
• Carbons of the pentose are designated N’ to alleviate confusion.
, Phosphate Group
• Negatively charged at neutral pH
• Typically attached to 5’ position
– Nucleic acids are built using the 5’-triphosphates version of the
nucleotide.
• ATP, GTP, TTP, CTP
– Two of the three phosphates used for building nucleic acids form a
leaving group, and completed nucleic acids contain one phosphate moiety
per nucleotide.
• May be attached to other positions for specialized function
Other Nucleotides: Monophosphate Group in
Different Positions
Structure & Function
Functions of Nucleotides and Nucleic Acids
• Nucleic acids are polymers of nucleotides used for:
– storage of genetic info (DNA)
– transmission of genetic info (mRNA)
– processing of genetic information (ribozymes)
– protein synthesis (tRNA and rRNA)
• Nucleotides are also used in the monomer form for cellular
functions:
– energy for metabolism (ATP)
– enzyme cofactors (NAD+, NADP+, FAD, FMN, Coenzyme A)
– signal transduction (cAMP)
– intermediates in biosynthetic reactions (UDP-glucose , SAM)
Nucleotides and Nucleosides
• Nucleotide =
– nitrogeneous base
– pentose
– phosphate
• Nucleoside =
– nitrogeneous base
– pentose
• Carbon AND nitrogen atoms on the nitrogenous base are numbered in
cyclic format.
• Carbons of the pentose are designated N’ to alleviate confusion.
, Phosphate Group
• Negatively charged at neutral pH
• Typically attached to 5’ position
– Nucleic acids are built using the 5’-triphosphates version of the
nucleotide.
• ATP, GTP, TTP, CTP
– Two of the three phosphates used for building nucleic acids form a
leaving group, and completed nucleic acids contain one phosphate moiety
per nucleotide.
• May be attached to other positions for specialized function
Other Nucleotides: Monophosphate Group in
Different Positions
