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.
Coordinates: 29Â°44â²N 90Â°06â²W / 29.733Â°N 90.100Â°W / 29.733; -90.100. Jefferson Parish (French: Paroisse de Jefferson) is a parish in the U.S. state of Louisiana. As of the 2010 census, the population was 432,552. The parish seat is Gretna. Jefferson Parish is included in the New Orleans-Metairie, LA Metropolitan Statistical Area. Jefferson Parish was less affected by Hurricane Katrina in 2005 and has rebounded at a more rapid pace than neighboring Orleans Parish.