Virus
A microscopic infectious agent that can only replicate inside living cells. Viruses consist of genetic material (DNA or RNA) surrounded by a protein coat, lacking the machinery for independent metabolism.
Used in the Books
This term appears in 8 chapters:
"If a cell's membrane displays the right markers, immune cells ignore it. If the markers are wrong - because it's a bacterial cell, or a virus-infected cell, or a cancerous cell that's lost its proper markers - immune cells attack. This is how organ transplants get rejected."
"...trolled growth is cancer.** A cancer diagnosis is terrifying because you realize your own body is trying to kill you. Not from outside invasion - no virus, no bacteria, no external threat. Your cells. Growing. Unstoppably. :::share{variant="blue" label="What Cancer Is"} Cancer is cells that forgot thre..."
"Expose yourself to cold and shiver - brown fat activates, making you more cold-resistant. Inject an attenuated virus - your immune system learns to destroy it. What doesn't kill you makes you stronger. But only at the right dose. The hormesis curve is simple: ..."
"...2 & 2017) Saudi Aramco, the world's largest oil company (state-owned by Saudi Arabia, valued at $2+ trillion), faced two major cyberattacks: Shamoon virus (2012) and Shamoon 2 (2017). Both attacks aimed to cripple Aramco's operations by destroying data and disabling systems."
"...enes from other individuals or species through transformation (uptake of environmental DNA), conjugation (direct transfer via pili), or transduction (virus-mediated transfer). Horizontal gene transfer (HGT) enables rapid acquisition of complex traits (antibiotic resistance, metabolic pathways) without wa..."
And 3 more chapters...
Biological Context
Viruses aren't considered fully alive—they're obligate parasites of cellular life. They evolve rapidly due to high mutation rates. Viruses drive evolution by transferring genes between organisms and by selecting for immune defenses.
Business Application
Viral business models hijack host systems to replicate—viral marketing uses social networks, viral products spread through user sharing. Like biological viruses, viral business strategies depend on host infrastructure they don't own or control.