Thermoreg.07

Thermoreg.07 - NOTE! These files are provided for the sole...

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0 NOTE!! These files are provided for the sole purpose of assisting BSci 110 students to study for exams in the class. Some of the material in these files may be copyrighted, and it is not OK for you to share these files with anyone who is not a student in this class or to use them for any purpose other than to study for the exams of our class. Thanks, Carl Johnson
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Thermoregulation 1
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Thermoregulation Living cells tolerate only a narrow range of temperature. Most cell function is limited to the range between 0°C and 45°C. However, some organisms are able to tolerate extremes. Thermal spring, Yosemite Hot Cold 2
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Thermoregulation Q 10 is defined as the rate of a reaction at a particular temperature (R T ) divided by the rate of that reaction at a temperature 10°C lower (R T-10 ). Q 10 = R T / R T-10 Most biological Q 10 values are ~ 2-3. Since not all of the component reactions in an organism have the same Q 10 , temperature change can disrupt the balance of physiological functioning. To maintain homeostasis, organisms must either compensate for or prevent temperature change. Purves 41.5 Most biochemical and physiological processes are temperature-sensitive, going faster at higher temperatures (up until proteins denature!). The sensitivity of a physiological process to temperature can be described as a quotient, Q 10 . Q 10 = 3 Q 10 = 2 Q 10 = 1 typical physiological range 3
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Thermoregulation Animals may be classified according to the sources of heat that determine their body temperature: Ectotherms (most animals aside from mammals and birds) depend on external heat sources to maintain body temperature. (for poikilotherms or "cold-blooded" animals, body temperature changes when environmental temperature changes.) Endotherms (all mammals and birds) regulate body temperature by generating metabolic heat and/or preventing heat loss. 4
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Thermoregulation If a lizard (an ectotherm) and a mouse (an endotherm) are placed in a closed chamber in which the temperature is gradually raised, the body temperature of the lizard will equilibriate with that of the chamber, whereas the body temperature of the mouse will remain constant. The metabolic rates also respond
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Thermoreg.07 - NOTE! These files are provided for the sole...

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