The Different Levels of Organization in Life

Atom is the smallest portion into which an element can be divided while still maintaining its essential properties. A molecule, as we've discussed before, is a group of at least two atoms that are held together by chemical bonds caused by the attraction between the positively charged nucleus and the negatively charged electrons in the electron shells. Macromolecules are very important in cell structure and understanding so on. The next level above atoms is molecules. Organelles are specialized subunit within a cell that has a specific function but also their own membrane.