Answers 100% Pass
Explain how the bird respiratory system differs from that of mammals - ✔✔-
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 - ✔✔they store air for short periods,
enabling fresh air to flow through the lungs during exhalation
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, -airflow into the parabronchi (gas exchange site) flows in only ONE direction---> O2
and co2 never mix
• explain the advantage of unidirectional airflow. - ✔✔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. - ✔✔bar-headed geese have an amino acid structure that is better
for high altitudes
Interpret the O2-Hb dissociation curves of normal (low altitude) and high-altitude birds
(e.g bar-headed geese) with respect to the PO2 available to them. - ✔✔high altitude is to
the left while normal is to the right.
Memorize and apply the binding rules of DNA bases - ✔✔T-->A
A-->U
C-->G
Explain the steps of protein synthesis, including the specific roles of; DNA, mRNA,
codons, start-codons, stop-codons, anticodons, tRNA, the genetic code, and ribosomes. -
✔✔1. DNA unravels which exposes the code
2. mRNA comes into the picture
3. Transcription begins to take place and copies the code from the DNA
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