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.
There are four kinds of nucleotides in a DNA molecule: cytosine, guanine, adenine, and thymineâC, G, A, and T, for short. Specific sequences of these bases, known as genes, form codes that contain all of an organism's genetic information.here are four kinds of nucleotides in a DNA molecule: cytosine, guanine, adenine, and thymineâC, G, A, and T, for short. Specific sequences of these bases, known as genes, form codes that contain all of an organism's genetic information.