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.
1 DNA contains four basic building blocks or â bases â: adenine (A), cytosine (C), guanine (G) and thymine (T). 2  The order, or sequence, of these bases form the instructions in the genome. 3  DNA is a two-stranded molecule. DNA contains four basic building blocks or â bases â: adenine (A), cytosine (C), guanine (G) and thymine (T). 2  The order, or sequence, of these bases form the instructions in the genome. 3  DNA is a two-stranded molecule.