1022J of energy can be related equal to which among the following?
Answers
Metabolism, which we will study in Chapter 20 "Energy Metabolism", is the collective term for the chemical
reactions that occur in cells and provide energy to keep cells alive. Some of the energy from metabolism is in the
form of heat, and some animals use this heat to regulate their body temperatures. Such warm-blooded animals
are called endotherms. In endotherms, problems with metabolism can lead to fluctuations in body temperature.
When humans get sick, for instance, our body temperatures can rise higher than normal; we develop a fever.
When food is scarce (especially in winter), some endotherms go into a state of controlled decreased metabolism
called hibernation. During hibernation, the body temperatures of these endotherms actually decrease. In hot
weather or when feverish, endotherms will pant or sweat to rid their bodies of excess heat.
Table 7.1 Average Body Temperatures of Selected Endotherms
Endotherm Body Temperature (°F) Body Temperature (°C)
bird up to 110 up to 43.5
cat 101.5 38.6
dog 102 38.9
horse 100.0 37.8
human 98.6 37.0
pig 102.5 39.2
Ectotherms, sometimes called cold-blooded animals, do not use the energy of metabolism to regulate body
temperature. Instead, they depend on external energy sources, such as sunlight. Fish, for example, will seek out
water of different temperatures to regulate body temperature. The amount of energy available is directly
related to the metabolic rate of the animal. When energy is scarce, ectotherms may also hibernate.
The connection between metabolism and body temperature is a reminder that energy and chemical reactions
are intimately related. A basic understanding of this relationship is especially important when those chemical
reactions occur within our own bodies.
Chapter 7 Energy and Chemical Processes