Once the DNA in a cell is replicated, the cell can divide into two cells, each of which has an identical copy of the original DNA. DNA replication is the process by which a double-stranded DNA molecule is copied to produce two identical DNA molecules.
The heart is a vital organ located in the center of the chest with a slight tilt to the left. Using rhythmic muscle contractions, it circulates blood through veins and arteries, which supplies tissues with oxygenated blood and disposes waste.
Â© 2014 WebMD, LLC. All rights reserved. The heart is a muscular organ about the size of a fist, located just behind and slightly left of the breastbone. The heart pumps blood through the network of arteries and veins called the cardiovascular system.The heart has four chambers: 1  The right atrium receives blood from the veins and pumps it to the right ventricle.2  The right ventricle receives blood from the right atrium and pumps it to the lungs, where it is loaded with oxygen. 3  The left atrium receives oxygenated blood from the lungs and pumps it to the left ventricle. 2014 WebMD, LLC. All rights reserved. The heart is a muscular organ about the size of a fist, located just behind and slightly left of the breastbone. The heart pumps blood through the network of arteries and veins called the cardiovascular system.