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.
A molecule of DNA is double-stranded. The molecule has the shape of a double helix, typically right handed (B form DNA).The DNA molecule consists of two complementary strands oriented in an antiparallel fashion. Each strand is composed of nucleotides. molecule of DNA is double-stranded. The molecule has the shape of a double helix, typically right handed (B form DNA).