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BIOB32H3- Final Exam Guide - Comprehensive Notes for the exam ( 36 pages long!)


Department
Biological Sciences
Course Code
BIOB32H3
Professor
Kenneth Welch
Study Guide
Final

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UTSC
BIOB32H3
Final EXAM
STUDY GUIDE

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Lecture 7: Thermoregulation
Body Teperature: The ost iportat eophysiologial paraeter
The ost ipotat ecophysiological paaete---temperature has the most important impact on
any form of life than almost any other parameter
Examples: how temperature influences some aspect of animals performance:
Brown Trout:
o Measure how long they can endure swimming at their maximal speed/capacity in different
water temperatures:
Water temperature does indeed have a profound impact on their endurance at
their maximal speed---endurance time only around 10 seconds when in very cold
and very warm temperatures but at intermediate temperatures, their endurance
is much longer (40 secs)
o Temperature is effecting the ability of these fish to swim which in turn affects how well
they can survive (how fast they are able to get away from predators)
Temperature has an effect on the physiology and by extension, the ecology of
these fish
House Gekko:
o One of the components of their immune system are phagocytic cells whose job is to
engulf/consume any pathogen within the body, use enzymes within them to break those
pathogens down and then just spit out those broken pieces for the rest of the immune
system to deal with
o Measure the capacity of these cells to carry out phagocytosis at different temperatures:
Capacity varies with temperature---only 10% of cells able to phagocytize at 7
degrees but 70% of cells can do so at 25 degrees
o Temperature is effecting the capacity of their immune systems to fight infection---a HG
at 25 degrees is 7-folds better at fighting infection than a HG at 7 degrees (affecting
physiology, affecting ecology)
The body temperature of an animal at any given point in time is determined by the total amount of
heat that is stored in that animal’s ody aial ody has lage aout of stoed heat higher body
temperature; lower amount of stored heat lower body temperature).
Body Temperature Regulation: Metabolic Heat
One of the ways that we can add (and only add here) to the stoed heat i a aial’s ody is though
the heat that is produced by metabolism
Second Law of thermodynamics: every chemical reaction has to produce some amount of heat---this
heat otiutes to the stoed heat i the aial’s ody ad theefoe, has the potetial to iease its
body temperature
Aythig that auses the aial’s etaolis to iease ould then also cause its body temperature
to then increase
The two most common ways by which any animal might see its metabolic rate increase is either
through activity or through feeding
o Study: (1) put lizards on treadmills and measured their oxygen consumption rate (MR)
while they either stood motionless at rest or ran at various speeds. (2) Two groups of
lizards in the study: fasting lizards and recently-fed lizards
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Lecture 7: Thermoregulation
(1) As the treadmill speed increases, volume of O2 consumed increases, MR
increases, body temperature increases
(2) Whether that lizard was at rest or was running very fast, recently-fed lizards
always had higher MRs (higher O2 volume consumed) than fasting lizards
Eating = MR increases (lasts for a couple of hours), body temperature
increases---specific dynamic action (or heat increment of feeding)---as a
result of all the biosynthetic activity the animal has to do in order to store
all the energy it has consumed
o Study: the Tawny owl can use the heat that is produced after it feeds in order to keep
itself warm: three groups of owls: (1) 20° (2) 5° (3) -5°. Feed all these owls the same
meal (3 entire mice)----if you’e eig fed the sae eal, the the “DA that is podued
should be the same in all three temperature cases---not really what happens
SDA highest: 20° owls, SDA much smaller: 5° owls, no SDA (no heat produced): -5°
owls
Why such big differences? At -5 and 5°, the owls are trying to keep themselves
warm so their fasting metabolism is already much higher (higher even for -5°)---the
colder it is, the more heat they have to produce while fasting just to stay warm.
Then when you feed them the mice, they substitute the new heat that is
produced (SDA) and replace the other heat they were already producing before
they fed to keep themselves warm.
Animals can indeed use this heat of feeding as a way of helping them to stay
warm, to regulate their body temperature, by essentially reducing how much
heat they have to produce by other mechanisms in order to stay warm
An animal that is fasting and at rest still has a metabolic rate that is significantly above 0---
Standard (or Basal) Metabolic Rate
What contributes to sustain this metabolic rate even when the animal is at rest and fasting?
o Protein Synthesis: maintaining the integrity of proteins as they break down over time (repair and
rebuild). This accounts for 1/3 of the oxygen you are consuming to maintain integrity of protein.
o Na+-K+ ATPase: Activity of this pump: maintains Na/K concentrations due to leaky membranes:
take Na from the ICF and pump into the ECF and take K from the ECF and pump into the ICF
How leaky the membrane is differs quite substantially between reptiles and mammals
Use radioactive K (to trace its movement) and inject into either kidney/liver cells
and measure how much K there is left inside the cells after some time has passed
o A lot of K still left in the cells of reptiles but very little K still left in the cells of
mammals (mammals have more leakier membranes---ATPase needs to work
much harder to maintain appropriate ion concentrations in mammals to
compensate for the greater leakiness---more O2/ATP being used up (higher
metabolism)---more heat being produced)
Meae Paeake Hypothesis: the SMR of animals correspond
to the leakiness of their cell membranes, how much ATPase pumping
needs to be done to maintain concentrations
The agitude of a aial’s stadad etaoli ate aies uite osidealy aog aial goups
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