In this way a DNA molecule is similar in structure to a ladder in which the sugar and phosphate groups make the uprights and the nitrogen base groups the rungs. There are four types of nitrogen bases or base groups. 1  Adenine (A). 2  Thyamine (T).3  Cytosine (C). 4  Guanine (G).he nucleotides in the DNA molecule are linked in series from one phosphate, to the next sugar, to the next phosphate and so on. The DNA molecule can be considered as a ladder with the phosphate and the sugar molecules making up the uprights and the bases making up the rungs.
Charleston Airport Shuttles. CHS airport has limousines and taxi services at low rates for incoming travelers. Charleston International Airport is South Carolinaâs busiest airport and is the oldest city of Charleston which rich in history and hospitality.
Charleston County is a county located in the U.S. state of South Carolina. As of the 2010 census, its population was 350,209, making it the third-most populous county in South Carolina (behind Greenville and Richland Counties). Its county seat is Charleston.