Attached to each sugar ring is a nucleotide base, one of the four bases Adenine (A), Guanine (G), Cytosine (C), and Thymine (T). The first two (A, G) are examples of a purine which contains a six atom ring and five atom ring sharing two atoms. The second two (C, T) are examples of a pyrimidine which is composed of a single six atom ring. A base pair is one of the pairs A-T or C-G. Notice that each base pair consists of a purine and a pyrimidine. The nucleotides in a base pair are complementary which means their shape allows them to bond together with hydrogen bonds. The A-T pair forms two hydrogen bonds. The C-G pair forms three.
Tamiflu is an antiviral medication used to treat flu symptoms caused by influenza. Learn about side effects, interactions and indications.
Medicines to prevent a migraine. Drugs used to prevent migraines include: 1  Anticonvulsants, such as topiramate. 2  AntidepressantsAntidepressants, such as amitriptyline. 3  Antihistamine, such as cyproheptadine. 4  Beta-blockers, such as propranolol. 5  Botulinum toxinBotulinum toxin, such as Botox. 6  Calcium channel blockers, such as verapamil. 7  Histamine.