Write short notes on the composition of DNA and RNA.

Composition of DNA:

Deoxyribonucleic Acid (DNA) is a double-stranded molecule found in the nuclei of cells and carries genetic information.
Nucleotides: DNA is composed of nucleotide units. Each nucleotide consists of three components: a deoxyribose sugar molecule, a phosphate group, and a nitrogenous base.
Deoxyribose Sugar: The sugar molecule in DNA is deoxyribose, which lacks an oxygen atom at the 2' carbon position compared to ribose sugar in RNA.
Phosphate Group: Each nucleotide contains a phosphate group, linking the sugar of one nucleotide to the phosphate of the next, forming a backbone for the DNA strand.
Nitrogenous Bases: There are four types of nitrogenous bases in DNA: adenine (A), cytosine (C), guanine (G), and thymine (T). Adenine pairs with thymine, and cytosine pairs with guanine through hydrogen bonds, forming the complementary base pairs that stabilize the double helix structure.
Composition of RNA:

Ribonucleic Acid (RNA) is a single-stranded molecule found in the cell nucleus and cytoplasm. It serves various roles in gene expression and protein synthesis.
Nucleotides: RNA is also composed of nucleotide units. Each nucleotide consists of three components: a ribose sugar molecule, a phosphate group, and a nitrogenous base.
Ribose Sugar: The sugar molecule in RNA is ribose, which contains an oxygen atom at the 2' carbon position.
Phosphate Group: Similar to DNA, RNA nucleotides also contain a phosphate group, forming a backbone for the RNA strand.
Nitrogenous Bases: There are four types of nitrogenous bases in RNA: adenine (A), cytosine (C), guanine (G), and uracil (U). Adenine pairs with uracil in RNA, and cytosine pairs with guanine, again forming complementary base pairs.
Key Differences:

Strandedness: DNA is double-stranded, while RNA is usually single-stranded.
Sugar Type: DNA uses deoxyribose sugar, and RNA uses ribose sugar.
Nitrogenous Base Pairs: In DNA, adenine pairs with thymine, while in RNA, adenine pairs with uracil.
Location: DNA is primarily located in the cell nucleus, while RNA can be found in the nucleus and the cytoplasm.
Roles: DNA stores genetic information, while RNA participates in various cellular processes, including protein synthesis (mRNA), transporting amino acids (tRNA), and catalyzing reactions (ribozymes).
Both DNA and RNA are essential molecules for the functioning of living organisms, with distinct roles in preserving genetic information and facilitating cellular processes.