IndietroStructures of Pyrimidines and Purines
01:17
Termini in questo insieme (20)
Purines are nitrogenous bases with a two-ring structure consisting of a six-membered and a five-membered nitrogen-containing ring fused together.
Pyrimidines are nitrogenous bases with a single six-membered nitrogen-containing ring.
The common purine bases are adenine (A) and guanine (G).
The common pyrimidine bases in DNA are cytosine (C) and thymine (T).
The common pyrimidine bases in RNA are cytosine (C) and uracil (U).
Two rings: one six-membered and one five-membered nitrogen-containing ring fused together.
One ring: a single six-membered nitrogen-containing ring.
Uracil (U) is unique to RNA and replaces thymine found in DNA.
Thymine (T) is unique to DNA and is replaced by uracil in RNA.
Adenine is a purine with a fused double ring system containing nitrogen atoms at positions 1, 3, 7, and 9.
Guanine is a purine similar to adenine but with a carbonyl group at position 6 and an amine group at position 2.
Cytosine is a pyrimidine with an amine group at position 4 and a carbonyl group at position 2.
Thymine is a pyrimidine with two carbonyl groups at positions 2 and 4 and a methyl group at position 5.
Uracil is a pyrimidine with two carbonyl groups at positions 2 and 4 but lacks the methyl group found in thymine.
Thymine has a methyl group at position 5, which uracil lacks.
Guanine, thymine, and uracil have keto (carbonyl) groups in their structures.
Adenine and cytosine have amino groups in their structures.
Adenine pairs with thymine via two hydrogen bonds, and guanine pairs with cytosine via three hydrogen bonds.
The complementary shapes and hydrogen bonding of purines and pyrimidines enable the double helix structure and accurate base pairing in DNA.
The fused ring system provides a larger planar structure that pairs with the smaller pyrimidine ring, maintaining uniform DNA helix width.