Which element is NOT a primary component of bacterial cells?

Bacterial cells are primarily composed of several key elements that are essential for their structure and function. These include carbon, hydrogen, nitrogen, oxygen, phosphorus, and sulfur.

Chlorine is not one of the primary components found in bacterial cells. While chlorine does play a role in various biochemical processes and is present in trace amounts in some biological systems, it does not serve as a fundamental building block for proteins, nucleic acids, or cell membranes as the other elements do.

Phosphorus, sulfur, and hydrogen, on the other hand, are critical for several cellular processes:

• Phosphorus is a vital component of nucleic acids (DNA and RNA) and is also found in ATP, the energy currency of the cell, making it crucial for energy transfer and storage.
• Sulfur is important for the structure of certain amino acids (like cysteine) and is involved in various metabolic reactions.
• Hydrogen is a major component of water and organic molecules, playing an essential role in cellular metabolism and energy production.

Hence, chlorine does not feature among the primary components of bacterial cells, making it the correct choice in this context.