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 DNA strand is made up of hundreds of thousands of nucleotides put together. A nucleotide is a type of molecule (organic molecule, to be specific) that is made up of a phosphate, a sugar, and a nitrogen base. In all DNA nucleotides, there is always the same phosphate and sugar. But the nitrogen bases differ. There are four nitrogen bases in DNA--Adenine, Guanine, Cytosine, and Thymine.