BRAINCAKEControl of Body Temperature
Mammals and birds keep their core body temperature (the temperature of the blood and the organs deep inside the body) within narrow limits. In humans this is about 37 °C. Controlling it is an example of homeostasis: keeping the internal environment within set limits despite changes outside.
The main reason is enzyme activity. Metabolic reactions are catalysed by enzymes, and every enzyme has an optimum temperature. If the core temperature falls, molecules have less kinetic energy, there are fewer successful enzyme-substrate collisions and metabolism slows. If it rises too far above the optimum, hydrogen bonds and other bonds holding the tertiary structure break, the active site changes shape and the enzyme is denatured. Denaturation is not reversed by cooling, so overheating is more dangerous than cooling.
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Key terms in this lesson
- denaturation
- A permanent change to the tertiary structure of a protein, such as an enzyme, usually caused by heat or extreme pH.
More in Homeostasis
- Extra Feedback
- Diabetes Insipidus
- Thermoregulation
- Losing or Gaining Heat
- Endotherms
- Ectotherms
- Thermoregulation in Endotherms
- The Skin
All 41 lessons in Homeostasis · All Edexcel A-level Biology topics