Understanding the differences between prokaryotic and eukaryotic cells is fundamental in biology. Prokaryotic cells are characterized by the absence of a nucleus, while eukaryotic cells possess a defined nucleus. This distinction is crucial as it reflects their complexity; prokaryotic cells are generally smaller, ranging from 1 to 10 micrometers, compared to the larger eukaryotic cells, which measure between 10 to 100 micrometers. The size difference contributes to the overall complexity of these cells, with prokaryotic cells being less complex and exclusively unicellular, whereas eukaryotic cells can be either unicellular or multicellular, forming the basis of all multicellular organisms.

Another significant difference lies in the structure of their DNA. Prokaryotic cells contain circular DNA, while eukaryotic cells have linear DNA. Additionally, prokaryotic cells lack membrane-bound organelles, which are present in eukaryotic cells. The methods of cell division also differ; prokaryotic cells undergo binary fission, a simpler process, whereas eukaryotic cells divide through mitosis and cytokinesis, which are more complex processes.

Ribosome size is another distinguishing feature: prokaryotic cells have smaller 70S ribosomes, while eukaryotic cells contain larger 80S ribosomes. Despite these differences, both prokaryotic and eukaryotic cells share some similarities. They both possess a cell membrane, which is essential for maintaining cellular integrity, and they contain the major biomolecules necessary for life, including carbohydrates, proteins, nucleic acids, and lipids. This foundational knowledge of cell types will be essential as we delve deeper into cellular biology.