Practice question

Thermus aquaticus was first isolated from high-temperature hot springs in Yellowstone National Park and grows optimally around 70-80°C. It thrives in such extreme thermal environments, classifying it as a thermophile, an extremophile adapted to sustain membrane integrity, enzymatic function, and protein stability under continuous thermal stress. Its DNA polymerase evolved to remain folded and catalytically active at near-boiling temperatures, resisting denaturation at 94-95°C used in PCR. Mesophiles grow at moderate temperatures, psychrophiles at cold, and halophiles in high salt, none supplying thermostable polymerase suitable for cyclical thermal denaturation.