Hint: DNA is a molecule that contains two polynucleotide chains that run anti-parallel to each other and contains the genetic code of an organism.
Complete answer: Deoxyribonucleic acid is the hereditary material in humans that contains the genetic code of organisms. It is responsible for bringing out the genetic variation in human beings. It is a double helical structure formed by two polynucleotide chains that are complementary and run anti-parallel to each other. A polynucleotide is a polymer of many nucleotides. These nucleotides are the building block of nucleic acids and consist of a sugar molecule, phosphate group, and nitrogenous bases. In a DNA molecule, deoxyribose is the sugar, and Adenine, Thymine, Guanine, and Cytosine are the nitrogenous bases. The basic structural unit of the DNA is called the nucleosome.
They are the repeating unit in the eukaryotic chromatin and give the appearance of beads on a string. It is formed by a section of DNA molecules and proteins. The proteins involved are the- highly basic histone proteins that form the core of the nucleosome. They help in the condensation of chromatin by wrapping the DNA tightly and compactly around itself. This condensation helps the DNA to fit inside the nucleus of a cell. A single nucleosome has around 150 base pairs of DNA. A strand of nucleosomes folds up to form chromatin fiber. Chromatin fibers are tightly packed to form chromosomes. Chromosomes are thread-like structures made up of DNA and proteins that are present inside the nucleus of a cell and carry genetic information from one generation to another. This packaging of DNA helps to adjust the 6 feet long DNA into the nucleus of each eukaryotic cell.
Each cell of a human body has DNA which is 6 feet long and has around 3 billion base pairs and contains 30,000 genes. The average number of cells in the human body is around 10 trillion. Therefore, the length of the entire human DNA will be around 10 billion miles. This 10 billion miles or 60 trillion feet DNA is packed in the human body into 46 chromosomes.
Note: Genome is the term used for the entire genetic material or DNA of an organism and its study is called genomics. The largest genome in the world is of a rare Japanese flower called Paris japonica whose genome is 50 times the size of the human genome.