CLINICAL MEDICINE

Detailed explanation-1: -Most intracellular bacteria and parasites carry the basic genetic information required for their own metabolism and replication, and they rely on their host cells only for nutrients.

Detailed explanation-2: -Viruses depend on the host cells that they infect to reproduce. When found outside of host cells, viruses exist as a protein coat or capsid, sometimes enclosed within a membrane. The capsid encloses either DNA or RNA which codes for the virus elements.

Detailed explanation-3: -A lysogenic virus remains inactive for a period of time. In the lysogenic cycle, the viral DNA gets integrated with the host’s DNA and gets copied when the host cell replicates.

Detailed explanation-4: -In humans, any cell that a pathogenic organism can invade is a host cell, e.g., human immune cells like CD4+ cells and macrophages are the host cell for HIV. It is essential to understand that only certain species of hosts or certain cells can serve as hosts for viruses or bacteria.