Is deoxyribose A purine or pyrimidine?
Table 17.1. 1: Composition of Nucleotides in DNA and RNA
| Composition | DNA | RNA |
|---|---|---|
| purine bases | adenine and guanine | adenine and guanine |
| pyrimidine bases | cytosine and thymine | cytosine and uracil |
| pentose sugar | 2-deoxyribose | ribose |
| inorganic acid | phosphoric acid (H3PO4) | H3PO4 |
What does purine pair with?
A with T: the purine adenine (A) always pairs with the pyrimidine thymine (T) C with G: the pyrimidine cytosine (C) always pairs with the purine guanine (G)
How many rings does a purine have?
Purine is a heterocyclic aromatic organic compound that consists of two rings (pyrimidine and imidazole) fused together. It is water-soluble. Purine also gives its name to the wider class of molecules, purines, which include substituted purines and their tautomers.
What are three examples of nucleic acids?
Examples of Nucleic Acids
- deoxyribonucleic acid (DNA)
- ribonucleic acid (RNA)
- messenger RNA (mRNA)
- transfer RNA (tRNA)
- ribosomal RNA (rRNA)
Where does the ribose in purine and pyrimidine come from?
The source of the ribose (or deoxyribose) sugar in the biochemical synthesis of purines and pyrimidines is 5-phosphoribosyl pyrophosphate (PRPP), which is derived from α-D-ribose-5-phosphate.
How are ribose bases attached to deoxyribose bases?
New molecules of ribose are attached to nitrogenous bases and phosphate groups before being deoxygenated into deoxyribose bases. The nucleotides can then be added to the growing string of bases which will become an independent DNA molecule. Ribose – A pentose molecule bound to 5 oxygen molecules, 1 more than deoxyribose.
What makes up the deoxyribose in a nucleic acid?
Each nucleic acid is composed of a deoxyribose molecule bound to both a phosphate group and either a purine or a pyrimidine. Purines have two carbon and nitrogen rings, while pyrimidines only have one ring. The purines are adenine (A) and guanine (G) while the pyrimidines are cytosine and thymine in DNA.
What is the role of PRPP in purine synthesis?
PRPP is substrate of three enzymes of purine metabolic pathway: PRPP amidotransferase, in de novo synthesis pathway, which serves specifically as the rate-limiting reaction for the purine synthesis, and HPRT and APRT in the salvage pathway. In addition to de novo synthesis of purine, PRPP is used in the pyrimidine and pyridine nucleotide synthesis.