https://en.wikipedia.org/wiki/PoikilothermFor an important chemical reaction, poikilotherms may have four to ten enzyme systems that operate at different temperatures.[4] As a result, poikilotherms often have larger, more complex genomes than homeotherms in the same ecological niche. Frogs are a notable example of this effect, though their complex development is likely more important.[5]
Because their metabolism is variable and generally below that of homeothermic animals, sustained high-energy activities like powered flight in large animals or maintaining a large brain is generally beyond poikilotherm animals.[6] The metabolism of poikilotherms favors strategies such as sit-and-wait hunting over chasing prey for larger animals with high movement cost. As they do not use their metabolisms to heat or cool themselves, total energy requirement over time is low. For the same body weight, poikilotherms need only 5 to 10% of the energy of homeotherms.[7]
A poikilotherm is an organism that cannot regulate its own body temperature and instead relies on external sources to maintain its body temperature.
Enzymes in poikilotherms have optimal activity at specific temperatures, which varies among different enzymes. When the temperature is too low, the enzymes may not work efficiently and at high temperatures, the enzymes can become denatured and lose their function.
The activity of enzymes in poikilotherms increases with an increase in temperature up to a certain point, where it reaches its optimal temperature. Beyond this point, the enzyme activity begins to decrease as the enzyme becomes denatured.
Enzymes in poikilotherms have a narrower temperature range for optimal activity compared to enzymes in homeotherms, which can regulate their own body temperature. Poikilotherms also have a lower tolerance for high temperatures as their enzymes can become denatured more easily.
No, once an enzyme in a poikilotherm is denatured due to high temperatures, it cannot be reversed. The enzyme will no longer function properly and can potentially cause harm to the organism. It is important for poikilotherms to maintain their body temperature within a narrow range to ensure optimal enzyme activity.