NEET BIOLOGY

Detailed explanation-1: -DNA base pair. Under normal circumstances, the nitrogen-containing bases adenine (A) and thymine (T) pair together, and cytosine (C) and guanine (G) pair together. The binding of these base pairs forms the structure of DNA .

Detailed explanation-2: -The nitrogen bases are ring compounds with their carbon and nitrogen atoms arranged in single or double rings. Only certain bases can pair together to form base pairs. In DNA, Adenine (A) always pairs with thymine (T), and guanine (G) always pairs with cytosine (C).

Detailed explanation-3: -A nucleotide is the basic building block of nucleic acids (RNA and DNA). A nucleotide consists of a sugar molecule (either ribose in RNA or deoxyribose in DNA) attached to a phosphate group and a nitrogen-containing base. The bases used in DNA are adenine (A), cytosine (C), guanine (G) and thymine (T).

Detailed explanation-4: -Hydrogen bond (H-bond) binds the nitrogen bases between the two strands of DNA. There are two H-bonds between A and T; three H-bonds between G and C.

Detailed explanation-5: -Every nitrogenous base shares one feature: a six-sided ring with 4 carbon atoms and 2 nitrogen atoms. A purine has an additional 5-sided ring, created by 1 more carbon and 2 more nitrogen atoms. A pyrimidine nitrogenous base has only 1 six-sided ring.