Compare and contrast a bacterium and a virus by writing either “Present” or “Absent” for each of the following structures.

Verified step by step guidance

1. Identify the key structural components typically found in bacteria and viruses. Common structures to consider include a cell wall, plasma membrane, cytoplasm, ribosomes, genetic material (DNA or RNA), and a protein coat (capsid).
2. Recall that bacteria are prokaryotic cells with a complex cellular structure, including a cell wall, plasma membrane, cytoplasm, ribosomes, and usually circular DNA. They do not have a protein coat like viruses.
3. Understand that viruses are acellular entities composed mainly of genetic material (either DNA or RNA) enclosed within a protein coat called a capsid. They lack a cell wall, plasma membrane, cytoplasm, and ribosomes.
4. For each structure listed in the problem, determine whether it is 'Present' or 'Absent' in bacteria by considering their cellular makeup, and do the same for viruses based on their simpler, non-cellular structure.
5. Summarize your findings in a comparative format, clearly marking 'Present' or 'Absent' for each structure in both bacteria and viruses, highlighting the fundamental differences in their biology.

Key Concepts

Structural Components of Bacteria

Bacteria are unicellular prokaryotes with complex structures including a cell wall, plasma membrane, cytoplasm, ribosomes, and sometimes flagella or pili. They possess DNA organized in a nucleoid and may have plasmids. Understanding these components helps identify which structures are present in bacteria.

Structural Components of Viruses

Viruses are acellular entities composed mainly of genetic material (DNA or RNA) enclosed in a protein coat called a capsid; some have an outer lipid envelope. They lack cellular structures like ribosomes and a plasma membrane, relying on host cells for replication. Recognizing viral structure is key to distinguishing them from bacteria.

Differences Between Cellular and Acellular Life Forms

Bacteria are living cells capable of independent metabolism and reproduction, while viruses are acellular and require host machinery to replicate. This fundamental difference explains the presence or absence of cellular structures and informs how to classify each structure as present or absent in the comparison.