This two-ringed structure has nine atoms forming the ring: 5 carbon atoms and 4 nitrogen atoms. Different purines are distinguished by the atoms or functional groups attached to the rings. Purines are the most widely occurring heterocyclic molecules that contain nitrogen.
They are abundant in meat, fish, beans, peas, and grains. Examples of purines include caffeine, xanthine, hypoxanthine, uric acid, theobromine, and the nitrogenous bases adenine and guanine.
Purines serve much the same function as pyrimidines in organisms. The molecules are used to make starch and proteins. While purines and pyrimidines include molecules that are active on their own as in drugs and vitamins , they also form hydrogen bonds between each other to link the two strands of the DNA double helix and to form complementary molecules between DNA and RNA.
In DNA, the purine adenine bonds to the pyrimidine thymine and the purine guanine bonds to the pyrimidine cytosine. In RNA, adenine bonds to uracil and guanine still bonds with cytosine. It's worth noting there are exceptions to the classic Watson-Crick base pairs. These are called "wobble pairings. The purines and pyrimidines both consist of heterocyclic rings. Together, the two sets of compounds make up the nitrogenous bases.
Yet, there are distinct differences between the molecules. Obviously, because purines consist of two rings rather than one, they have a higher molecular weight. The ring structure also affects the melting points and solubility of the purified compounds.
The human body synthesizes anabolism and breaks down catabolism the molecules differently. The end product of purine catabolism is uric acid, while the end products of pyrimidine catabolism are ammonia and carbon dioxide. The body does not make the two molecules in the same location, either. Purines are synthesized primarily in the liver, while a variety of tissues make pyrimidines.
Here is a summary of the essential facts about purines and pyrimidines:. Purines have two carbon-nitrogen rings and pyrimidines have one carbon-hydrogen ring.
Explanation: Both are nitrogenous bases. Adenine and guanine are purines, while thymine, cytosine, and uracil are pyrimidines. Related questions What are large biochemical molecules?
How do polar molecules enter cells? Question 7af What is UREX? The Pyrimidines are the final products of the catabolism between the beta-amino acids and the ammonia and carbon dioxide. The pyrimidines that are synthesized from the nucleic acids, with the help of nucleotidases and the pyrimidine nucleoside phosphorylase, form the four-amino group of cytosine and five-methylcytosine.
It releases ammonia and carbon dioxide. Since the purines and pyrimidines are heterocyclic, they can come together to form several nitrogenous bases. However, since purines are made up of two rings instead of one, they have a heavier molecular weight than that of others.
The circular ring structure plays its role in the melting points and solubility of these compounds. The aforementioned ways represent how these molecules are synthesized and broken down differently by the body in different places, as the purines are manufactured in the liver and the pyrimidines in the tissues.
Double carbon-nitrogen ring with 4 Nitrogen atoms. Single carbon-nitrogen ring with two nitrogen atoms. Larger in size. Smaller to Purines. Melting Point.
Molar Mass. Adenine and Guanine. Solubility in Water.
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