The cell is an interactive and, for the most part, self-sustaining unit. It is the smallest unit of life, which means that the components of cells are not capable of performing the complex life-related behaviors that cells exhibit. Biomolecules organize themselves into cells and, with the increasing level of organization, different properties emerge. Emergent properties are those characteristics not formerly present and that appear as a result of increased complexity or organization. All cells are organized, processing energy, undergo growth and development, maintain homeostasis, and reproduce.



There are two types of cells: prokaryotic and eukaryotic. Prokaryoticcells contain neither a nucleus nor membrane-bound organelles. However, prokaryotic cells have DNA and several specialized structures.

Eukaryotic cells are larger and much more complex than prokaryotic cells. Their size presents a challenge in fact. With increasing size, the ratio of surface area to volume becomes smaller. Such a decrease in surface to volume ratio results in challenges to sustain life processes. Eukaryotic cells have, therefore, evolved small compartments or organelles that both increase the membrane ratio and isolate “cellular jobs” for more efficiency.

Watch the video on prokaryotic and eukaryotic cells.