Nucleic Acids, Proteins, and Enzymes Flashcards
Nucleic Acids
Polymers specialized for storage, transmission, and use of genetic information
Two Main Nucleic Acids
DNA and RNA
Nucleotides
Monomers of nucleic acids. Consist of a pentose (5-carbon) sugar, a nitrogen-containing base, plus 3 phosphate groups
Difference between ribose (RNA) and deoxyribose (DNA)
The two pentoses differ only at the 2C position. Ribose has a hydroxy group, whereas deoxyribose does not.
Purine
Nitrogen base containing two fused rings (A and G)
Pyrimidine
Nitrogen base containing one ring (C, T, and U)
The base is always connected to the ___ carbon of the sugar.
The base is always connected to the 1 carbon of the sugar.
The phosphate groups are always connected to the ____ carbon of the sugar.
The phosphate groups are always connected to the 5 carbon of the sugar.
Phosphodiester Bonds
Formed by nucleotides bonding together in condensation reactions. Linkage occurs between the phosphate group of one nucleotide and the 3’ OH group of another’s ribose. Nucleic acid chains grow (extend) in the 5’ to 3’ direction
3’ End
Has a free 3’ hydroxyl group
5’ End
Has the phosphate group(s) exposed.
Directionality
Property of DNA and RNA caused by each strand having two chemically distinct ends
Antiparallel
Property of the DNA double helix wherein the two strands of DNA run in opposite directions
Complementary Base Paring (DNA)
Adenine-Thymine (A-T) base pairs always form two H-bonds; Guanine-Cytosine (G-C) base pairs always form three H-bonds.
Complementary Base Pairing (RNA)
Adenine-Uracil (A-U) pairs always form two H-bonds. Guanine-Cytosine (G-C) pairs always form three H-bonds.
