Acellular

Definition

Acellular organisms lack cellular structure and are not composed of cells. Viruses are a prime example, consisting solely of genetic material enclosed in a protein coat.

5 Must Know Facts For Your Next Test

1. Viruses are classified as acellular because they do not have cellular structures like cytoplasm or organelles.
2. Acellular organisms cannot carry out metabolic processes on their own and rely on host cells for replication.
3. Unlike cellular organisms, acellular entities such as viruses do not grow or respond to stimuli independently.
4. Viruses can infect all types of life forms, from animals and plants to bacteria and archaea.
5. The study of acellular organisms is essential for understanding infectious diseases and developing vaccines.

Review Questions

• What structural component is absent in acellular organisms that is present in cellular organisms?
• Why can't acellular organisms perform metabolic processes without a host?
• How do viruses replicate if they are acellular?

Related terms

Virus: Infectious agent composed of nucleic acid enclosed in a protein coat, requiring a host cell for replication

Host Cell: A living cell in which a virus replicates after infecting it

Protein Coat (Capsid): The outer layer of proteins that encloses the genetic material of a virus