The correct structure of DNA components can be presented as The correct structure of DNA monomers can be presented as Multiple Choice phosphate-base-sugar COS O phosphate-sugar-base. base-phosphate-
The Correct Answer and Explanation is :
The correct answer is: phosphate-sugar-base
Explanation:
DNA (deoxyribonucleic acid) is a molecule composed of monomers known as nucleotides. Each nucleotide consists of three primary components: a phosphate group, a sugar molecule (deoxyribose in DNA), and a nitrogenous base. These components are connected in a specific order to form the structure of DNA.
- Phosphate Group: The phosphate group consists of a phosphorus atom bonded to four oxygen atoms and is negatively charged. This group forms the backbone of the DNA strand, linking together the sugars of adjacent nucleotides through phosphodiester bonds.
- Sugar Molecule: In DNA, the sugar is deoxyribose, a five-carbon sugar that provides a stable framework for the nucleotide. The sugar in each nucleotide is attached to both the phosphate group and the nitrogenous base. The sugar is named “deoxyribose” because it lacks an oxygen atom at the 2′ carbon (unlike ribose found in RNA).
- Nitrogenous Base: The nitrogenous bases are adenine (A), thymine (T), cytosine (C), and guanine (G). These bases are categorized into two groups:
- Purines: adenine and guanine.
- Pyrimidines: cytosine and thymine.
The bases are paired specifically: adenine pairs with thymine, and cytosine pairs with guanine, through hydrogen bonds. These base pairs form the rungs of the DNA double helix.
DNA has a double helix structure, where two long strands of nucleotides twist around each other, held together by complementary base pairing. The order of the nitrogenous bases along a strand of DNA encodes genetic information, and the sequence of bases forms the “genetic code.”
The correct arrangement of these components within a nucleotide is phosphate-sugar-base, where the phosphate group is attached to the 5′ carbon of the sugar, and the base is attached to the 1′ carbon of the sugar. This structure allows the formation of a long polymer chain of nucleotides, which is essential for the functions of DNA, such as replication and protein synthesis.