What is pyrimidine and purine?
Purines and pyrimidines are the nitrogen bases that hold DNA strands together through hydrogen bonds. The purines in DNA are adenine and guanine, the same as in RNA. The pyrimidines in DNA are cytosine and thymine; in RNA, they are cytosine and uracil.
What are the 4 purine bases?
Each purine base can only form a bond with one pyrimidine base, adenine with thymine and guanine with cytosine. As a result, there are four possible combinations: adenine-thymine, thymine-adenine, guanine-cytosine and cytosine-guanine.
How many purines and pyrimidines are there?
Purines consist of a six-membered and a five-membered nitrogen-containing ring, fused together. Pyridmidines have only a six-membered nitrogen-containing ring. There are 4 purines and 4 pyrimidines that are of concern to us.
What are pyrimidine examples?
Examples of pyrimidines are cytosine, thymine, and uracil. Cytosine and thymine are used to make DNA and cytosine and uracil are used to make RNA.
Which of the 5 bases are pyrimidines?
The pyrimidine bases are thymine (5-methyl-2,4-dioxipyrimidine), cytosine (2-oxo-4-aminopyrimidine), and uracil (2,4-dioxoypyrimidine) (Fig. 6.2).
What are purines and pyrimidines Class 12?
Purine is a heterocyclic aromatic organic compound composed of a pyrimidine ring fused with imidazole ring. Pyrimidine is a heterocyclic aromatic organic compound that is composed of carbon and hydrogen. It comprises adenine and guanine as nucleobases.
What are the pyrimidine bases?
The pyrimidine bases are thymine (5-methyl-2,4-dioxipyrimidine), cytosine (2-oxo-4-aminopyrimidine), and uracil (2,4-dioxoypyrimidine) (Fig. 6.2). Figure 6.2. Pyrimidine bases. Purine bases include adenine (6-aminopurine) and guanine (2-amino-6-oxypurine) (Fig.
What are the 5 nitrogenous bases?
Five nucleobases—adenine (A), cytosine (C), guanine (G), thymine (T), and uracil (U)—are called primary or canonical. They function as the fundamental units of the genetic code, with the bases A, G, C, and T being found in DNA while A, G, C, and U are found in RNA.
How many carbons are in purines?
The pyrimidine bases have a 6‐membered ring with two nitrogens and four carbons. The purine bases have a 9‐membered double‐ring system with four nitrogens and five carbons.
Do purines have Deoxyribose?
The sugar is deoxyribose in DNA and ribose in RNA. The purines have a double ring structure with a six-membered ring fused to a five-membered ring. Pyrimidines are smaller in size; they have a single six-membered ring structure. The sugar is deoxyribose in DNA and ribose in RNA.
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