Final answer:
Cold-adapted enzymes are more efficient at low temperatures due to increased flexibility at their active sites, which allows them to effectively bind substrates even at reduced kinetic energy conditions like cold environments. These enzymes have lower optimal temperatures compared to human enzymes. Organisms use thermoregulation mechanisms to maintain enzyme function within optimal temperature ranges.
Step-by-step explanation:
The reason cold-adapted enzymes are more efficient at low temperatures than their warm-adapted counterparts is primarily due to their increased flexibility at the active site. This allows the enzyme to bind to its substrates more easily at cold temperatures. Bacteria that thrive in cold environments, such as refrigeration bacteria, have enzymes with optimum temperatures near 4°C, which is significantly lower than the human body's enzymes that have optimal activity between 37°C and 40°C. The increase in flexibility of these enzymes compensates for the reduced kinetic energy of substrate molecules at lower temperatures, thereby maintaining the necessary reaction rates for the survival of the organism.
Conversely, enzymes in humans and other warm-blooded animals typically denature and lose function at high temperatures, around 50°C for mammals. This is why thermoregulation mechanisms like hibernation, aestivation, or migration are vital for maintaining body temperature and enzyme function within an optimal range. Species may have greater cold tolerance in colder parts of their range due to these adaptive evolutionary adjustments to enzymes and other macromolecules.