Understanding Cell Theory
Cell Theory is a fundamental concept in biology that describes the properties of cells. It states that:
- All living organisms are composed of one or more cells.
- The cell is the basic unit of life.
- All cells arise from pre-existing cells.
Organisms in Context
When evaluating the listed organisms in relation to Cell Theory:
- Bacteria: These are unicellular organisms that fit perfectly within Cell Theory, as they are composed of cells and display all characteristics of life.
- Fungi: This group includes multicellular and unicellular organisms (like yeast) that are also made up of cells, adhering to the principles of Cell Theory.
- Plants: These multicellular organisms are composed of plant cells, which also fit into Cell Theory, fulfilling all its criteria.
- Viruses: Unlike the above organisms, viruses do not fit into Cell Theory for several reasons:
- Non-cellular Structure: Viruses lack cellular structure; they do not have a cell membrane or cellular machinery.
- Reproduction Dependency: Viruses cannot reproduce independently; they must infect a host cell and hijack the host's cellular machinery to replicate.
- Lack of Metabolism: Viruses do not exhibit metabolic processes outside a host organism, further separating them from cellular life.
Conclusion
In summary, while bacteria, fungi, and plants are all cellular organisms that align with Cell Theory, viruses are acellular entities that do not meet the criteria, making option 'B' the correct answer.