The nucleus contains the chromosomes of the cell. The main genome of the organism is found in the nucleus. In humans, the nucleus holds 46 chromosomes, which contains about 25,000 genes. However, mitochondria have DNA of their own.The human mitochondrion has DNA in the form of plasmids, which are circular pieces of DNA. Mitochondrial genes encode for 13 proteins and 24 RNA molecules that are only found in the mitochondrion.he nucleus contains the chromosomes of the cell. The main genome of the organism is found in the nucleus. In humans, the nucleus holds 46 chromosomes, which contains about 25,000 genes. However, mitochondria have DNA of their own.
Print. The heart has two upper and two lower chambers. The upper chambers, the right and left atria, receive incoming blood. The lower chambers, the more muscular right and left ventricles, pump blood out of your heart.The heart valves, which keep blood flowing in the right direction, are gates at the chamber openings.he heart has two upper and two lower chambers. The upper chambers, the right and left atria, receive incoming blood.
The heart is a muscle. It has four chambers that pump blood. The upper two chambers are called the atria and the lower two chambers are called the ventricles.. The heart is really two pumps that work together to move blood through the body.The right-sided pump fills with blood returning from the body and pumps it to the lungs to receive oxygen.This right-sided pump is a thinner muscle than the left-sided pump because it only has to pump blood to the lungs. The left side of the heart receives blood from the lungs and pumps it out to all parts of the body.he heart is a muscle. It has four chambers that pump blood. The upper two chambers are called the atria and the lower two chambers are called the ventricles.. The heart is really two pumps that work together to move blood through the body.