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Biology 2601A/B Lecture Notes - Thermometer, Electrochemical Gradient, Membrane Fluidity

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BIOL 2601A/B

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Organismal Physiology Lecture
Sept 11, 2012
Humans have flexibility; we can produce shlter, clothing, etc, we can survive in
different temperatures
Other organisms live in extreme environments (like penguins- don’t build shelter
but they cuddle together)
Tree on the right lives in an extremely hot and dry environment
Temperature definition- know this
Difference between temp and heat: temp is caused by intensity of motion at a
molecular level, heat is the amount of energy actually in an object: 2 blocks with the
same temperature, but if one has twice the mass it has twice the heat
Heat is always transferred from warm to cool
Eqwuation: energy balance equation for any organism (or object)
When the equation equals 0 the object is not gaining or losing energy
Direct radiontion from the sun, indirect radiation bouncing off of shit, radiation
from the sky, amount of infared radtiation is dependent on the temperature of the
object- you also emit radiation
Convective potential; windier it is the faster its moving heat away from you
Conduction; the transfer of nrg through solids (sit on a warm rock)
Metabolism: some have metabolic heat and some dont
Latent heat loss (L): water evaporation or condensation
Thermometer slide: showing us the scales we will be working with
Absolute zero= no atomic motion
Some organisms can be frozen in liquid nitrogen and survive when they unthaw
Some extremophiles can survive much higher temperatures
Tb= body temperature
Regional: an animal that might be walking on ice or something
Oxygen consumption is a measure of metabolic activity; the metabolic rate increases
as the organism gets hotter
M= resting metabolic rate
A= constant
N= constant
Tb= body temp
If you put the metabolic rate on a log scale instead of a linear scale, the relationship
becomes linear as opposed to exponential
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Q10= how much does that rate change when you change the temperature 10
Rt= rate of given temp
Roughly exponential, the impact of a 10 degree change depends on which interval
you’re looking at. If you’re measuring between 20 and 30 degrees it’s a dramatic
effect, mediocre effect from 10-20, small effect from 0-10
Respiration is an exponential function (warm the leaves respiration icreases
The warmer the enzyme is the weaker the affinity for the substrate
Substrate a interacts with the enzyme to produce product b
V max is the maxiumum rate or velocity of the reaction (where does it saturate)
Km= amount of substrate to get to ½ vmax
Enzyme substrate affinity: inverse of the Km (high km= low affinity)
Warmer generally means faster
Photoperiod: day length, doesn’t change, animals don’t usualy depend purely on
temperature bevause it can very (warm spring, suddenly its cold again)
Seasonality is photoperiod dependent
Once there is metabolic heat in the komoto dragon it has a lot of volume so it can
stay warm for a long time, less surface area for it to be lost from, more volume for it
to keep it
Higher temps you might need a lot of oxygen but you may not be able to deliver it
fast enough
Membrane fluidity gets cold and hard and brittle and cant operate properly, too hot
it gets all melty and fluid and leaky (modify membrane composition to fix this)
Enxyme denaturation (usually occurs between 50-70 degrees)
Blue lines are where they operate, aside fro that they wont be very effective
Readings are on webct
(start of 2nd lecture, kind of recaps 1st lecture)
We as humans are homeotherms
Temperatures fluctuate a lot but we want to keep them relatively stable
Mammals are separated from the birds
Referred to as a physiological convergence
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