Bio 1500 Exam 5 Questions And Answers
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Explain how the bird respiratory system differs from that of mammals - Answer✔-parabronchi:
site of gas exchange (comparable to our alveoli); fixed shape
-air sacs: store fresh and used air
-lungs: gas-exchange surface in the bird respiratory system (where does oxygen enter the blood
and carbon dioxide leave the blood)
Bird lungs don't expand/contract like mammal lungs, exchange of o2 happens in microscopic
sacs
Air flow in parabronchi in 1 direction only
*Atmospheric pO2 in lung*
explain the function of the air sacs and how the airflow in birds directs oxygen-rich air through
the lungs at all stages of respiration - Answer✔they store air for short periods, enabling fresh
air to flow through the lungs during exhalation
airflow into the parabronchi (gas exchange site) flows in only ONE direction
---> O2 and co2 never mix
explain the advantage of unidirectional airflow - Answer✔there is less mixing of fresh and 'used'
air
explain why the high efficiency respiratory system of birds does not work sufficiently well at
high altitude - Answer✔bar-headed geese have an amino acid structure that is better for high
altitudes
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interpret the O2-Hb dissociation curves of normal (low altitude) and high-altitude birds(e.g bar-
headed geese)with respect to the PO2available to them. - Answer✔Bar headed: look this up
Greylag goose have - Answer✔proline
Bar headed geese have - Answer✔alanine
Advantage of alanine over proline? - Answer✔Alanine is a smaller AA, results in a gap which
makes the structure looser and facilitates o2 binding
-Substituting alanine for proline changes the quaternary structure, shifting its o2 dissoc. curve
to the left (higher affinity for o2)
Air flow in birds - Answer✔(inhale) trachea --> posterior/rear air sacs --> parabronchi -->
anterior/front air sacs --> trachea --> leaves the body
There is fresh air in parabronchi in both inhalation and exhalation
function of myoglobin in the body - Answer✔stores O2 in slow/endurance muscles
red protein containing heme that carries and stores o2 in muscle cells
explain how the structure and the O2 binding properties of myoglobin relate to each other. -
Answer✔
myoglobin is made up of - Answer✔1 heme & 1 globin
memorize the basic structure and function of hemoglobin - Answer✔Structure:
-4 globular protein subunits(2 alpha & 2 beta)
-4 heme groups (w/iron -- bind O2)
Heme group, porphyrin ring, iron ion
Function:
-O2 transport pigment in vertebrates
-makes blood red
-located in RBC
-carries up to 20x more o2 than when o2 is dissolved
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