1 Chronic bronchitis: A form of COPD characterized by a chronic productive cough. 2  Emphysema: Lung damage allows air to be trapped in the lungs in this form of COPD. 3  Difficulty blowing air out is its hallmark. 4  Acute bronchitis: A sudden infection of the airways, usually by a virus.
There are only 46 DNA molecules ( 23 pairs) in human somatic cell. There are about 22000 genes and close to 3.2 billion base pairs in total.
The DNA molecule is technically classified as a bipolymer, which means that it contains two polymer chains that link up to form the larger molecule. Each of these polymer chains is composed of a DNA monomer, or nucleotide, whose structure is formed from a phosphate group, a deoxyribose sugar and a nitrogen-containing base. The deoxyribose sugar forms part of the backbone of each DNA strand, which line up along the outside of the whole DNA molecule.