CK-12 Foundation
Ck 12: Life Science: Cell Biology
[Free Registration/Login may be required to access all resource tools.] A cell is the smallest structural and functional unit of an organism. Learn more about cell biology in this learning module produced by CK-12.
CK-12 Foundation
Ck 12: Biology: Cell Biology
[Free Registration/Login may be required to access all resource tools.] Introduces cells, cell theory, and the levels of organization in organisms.