DNA replication is the process by which DNA makes a copy of itself during cell division. 1  The first step in DNA replication is to âunzipâ the double helix structure of the DNA molecule.
The heart is a muscular organ in humans and other animals, which pumps blood through the blood vessels of the circulatory system. Blood provides the body with oxygen and nutrients, and also assists in the removal of metabolic wastes. The heart is located in the middle compartment of the mediastinum in the chest.
The Heartbeat. Your heart is a muscular organ that acts like a pump to continuously send blood throughout your body. Your heartbeat occurs when the atria and ventricles work together, alternately contracting and relaxing to pump blood through your heart.The electrical system of your heart is the power source that makes this possible.our heart is a muscular organ that acts like a pump to continuously send blood throughout your body. Your heartbeat occurs when the atria and ventricles work together, alternately contracting and relaxing to pump blood through your heart. The electrical system of your heart is the power source that makes this possible.