In bacteriophages, which structure directly protects the viral DNA from degradation and environmental damage outside the host cell?

• A. Host restriction endonucleases
• B. The bacterial ribosome
• C. The protein capsid (head)
• D. The tail fibers

Answer: (C)

Verified step by step guidance

1. Understand the role of each structure listed in the problem: Host restriction endonucleases are enzymes in bacteria that cut foreign DNA, the bacterial ribosome is involved in protein synthesis, tail fibers help the virus attach to the host cell, and the protein capsid (head) encloses the viral DNA.
2. Recall that the viral DNA needs protection from physical, chemical, and enzymatic damage when the virus is outside the host cell, which is a harsh environment.
3. Identify which structure acts as a protective shell around the viral DNA, shielding it from degradation and environmental factors.
4. Recognize that the protein capsid (head) is a robust protein coat that encases the viral genome, providing this protection.
5. Conclude that among the options, the protein capsid (head) is the structure that directly protects the viral DNA outside the host cell.