Best Answer: The definitions will tell you the differences. The nucleus, in a eukaryotic cell, contains the DNA for cell function and, therefore, is the control center of the cell (It is NOT a brain).It also contains the nucleolus which is the site where ribosomes are manufactured.he nucleus, in a eukaryotic cell, contains the DNA for cell function and, therefore, is the control center of the cell (It is NOT a brain). It also contains the nucleolus which is the site where ribosomes are manufactured.
The heart contains four chambers. The two upper chambers are the atria and the two lower chambers are the ventricles. On the cranial surface of each atrium is a pouch-like appendage called an auricle which is thought to increase the capacity of the atrium slightly.
The atrium is a chamber in which blood enters the heart, as opposed to the ventricle, where it is pushed out of the organ. The atrium receives blood as it returns to the heart to complete a circulating cycle, whereas the ventricle pumps blood out of the heart to start a new cycle.Mammalian heart has 4 chambers-.