Written by the Fiveable Content Team • Last updated September 2025
Written by the Fiveable Content Team • Last updated September 2025
Definition
Noncellular entities do not consist of cells and lack cellular structures such as a nucleus or membrane-bound organelles. Examples include viruses which rely on host cells for replication and survival.
5 Must Know Facts For Your Next Test
Noncellular entities like viruses are incapable of independent metabolism and must infect host cells to reproduce.
Viruses consist of genetic material, either DNA or RNA, encased in a protein coat called a capsid.
Noncellular organisms do not engage in cellular processes like respiration or photosynthesis.
They exhibit high mutation rates which contribute to their evolutionary adaptations.
Viruses can infect all forms of life, from animals and plants to bacteria and archaea.
Review Questions
Related terms
Virus: A microscopic infectious agent that can only replicate inside the living cells of an organism.
Capsid: The protein shell that encases the genetic material of a virus.
Host Cell: A living cell in which a virus replicates using the cell's machinery.