Report Abuse. All eukaryotic cells (which means  has true nucleus) have a nucleus. However, certain cells called Prokaryotic cells (meaning no true nucleus) do not have a nucleus. Instead, their genetic data simply floats around the inside of the cell like water outside of a glass.All plants and animals have very complex Eukaryotic cells.The main difference between plant cells and animal cells, rather than nucleus or no nucleus, is that plants have an extra protective layer around the cell called a cell wall.ll plants and animals have very complex Eukaryotic cells. The main difference between plant cells and animal cells, rather than nucleus or no nucleus, is that plants have an extra protective layer around the cell called a cell wall.