DNA and RNA Bases. In DNA, there are four different bases: adenine (A) and guanine (G) are the larger purines. Cytosine (C) and thymine (T) are the smaller pyrimidines.
Gretna is the second-largest city and parish seat of Jefferson Parish, Louisiana, United States. Gretna is on the west bank of the Mississippi River, just east and across the river from uptown New Orleans. It is part of the New Orleans â Metairie â Kenner Metropolitan Statistical Area. The population was 17,736 at the 2010 census.
Gretna is part of the Tallahassee, Florida Metropolitan Statistical Area. Gretna is located at 30Â°36â²56â³N 84Â°39â²45â³Wï»¿ / ï»¿30.61556Â°N 84.66250Â°Wï»¿ / 30.61556; -84.66250 (30.615598, -84.662457). According to the United States Census Bureau, the city has a total area of 1.9 square miles (4.9 km 2), all land.