The bases which are present in human DNA?
**Core Concept**
DNA (deoxyribonucleic acid) is a double-stranded helix composed of nucleotides, each containing a sugar molecule (deoxyribose), a phosphate group, and one of four nitrogenous bases: adenine (A), guanine (G), cytosine (C), and thymine (T). These nitrogenous bases are the fundamental building blocks of DNA, playing a crucial role in determining the genetic code.
**Why the Correct Answer is Right**
The nitrogenous bases in DNA are responsible for storing genetic information and transmitting it from one generation to the next. Adenine (A) and guanine (G) are purine bases, while cytosine (C) and thymine (T) are pyrimidine bases. During DNA replication, the base pairing rules (A-T and G-C) ensure accurate transmission of genetic information. The sequence of nitrogenous bases determines the genetic code, which ultimately controls the synthesis of proteins and the functioning of cells.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is not a valid choice for the question.
**Option B:** This option is not a correct list of nitrogenous bases in human DNA.
**Option C:** This option is not a correct list of nitrogenous bases in human DNA.
**Clinical Pearl / High-Yield Fact**
The base pairing rules in DNA replication are A-T and G-C, which ensures accurate transmission of genetic information. This fundamental concept is crucial for understanding genetic inheritance and the functioning of cells.
**Correct Answer: A. Adenine (A), Guanine (G), Cytosine (C), Thymine (T)**