Final answer:
Viruses are exceptions to the cell theory structure as they are acellular and cannot carry out life processes without a host cell.
Step-by-step explanation:
The organism that is considered an exception to the cell theory structure is a virus. Unlike other organisms, viruses are acellular and do not have cells. They are composed of genetic material (DNA or RNA) surrounded by a protein coat. Viruses are classified as non-living because they cannot carry out life processes without a host cell.
Learn more about exceptions to the cell theory structure