Bacteria (Living)
* Cellular Structure: Bacteria are single-celled organisms (prokaryotes) with a complex internal structure. They have:
* Cell membrane: A protective outer layer
* Cytoplasm: The gel-like substance within the cell
* Ribosomes: Tiny structures for protein synthesis
* DNA: Genetic material organized into a single circular chromosome
* Some may have: Cell walls, flagella (for movement), pili (for attachment)
* Metabolism: Bacteria can obtain energy and create their own building blocks (like proteins) through various metabolic processes. They can reproduce independently.
* Growth and Reproduction: Bacteria grow and reproduce independently through binary fission, where they simply split into two identical copies.
* Evolution: Bacteria evolve and adapt to their environment over time due to mutations in their DNA.
Viruses (Non-Living)
* Acellular: Viruses are not made up of cells. They consist of:
* Genetic material: DNA or RNA enclosed within a protein coat (capsid)
* Some viruses also have: an outer envelope derived from the host cell membrane
* No independent metabolism: Viruses cannot obtain energy or create their own building blocks. They rely entirely on a host cell for these functions.
* Replication: Viruses can only replicate (multiply) within a living host cell. They insert their genetic material into the host cell's DNA, hijacking the cell's machinery to produce more viruses.
* No growth or evolution (on their own): Viruses do not grow in the sense that bacteria do. They can evolve, but only by adapting to changes in their host cells.
In summary:
Bacteria are considered living organisms because they are cellular, have their own metabolism, can grow and reproduce independently, and evolve over time. Viruses, lacking these essential characteristics, are classified as non-living entities.
