Exam

[Nelsson]

SInce I have my zoo physiology exam coming up in just a few days, have I been reviewing some of the old exams in the course. However, I'm unable to answer some of them, and I can't find any answers in my textbook: "Biology 7.th ed. - Campbell & Reece". Perhaps these issues no longer are considered important, curriculum - wise. Nevertheless, I would appreciate it if i could get some answers here, so I can be prepared as best I can before my exam. The questions are:

Some insects get rid of their CO2 in a cyclic manner. What physiological processes are involved and what is the purpose of this adaptation?

Next: Explain how the dissociation curve of Oxygen changes with changes in a) temperatur b) CO2 - consentration c) pH ? I'm a bit confused by this. I thought CO2 concentration and pH changes was closely related. With increased CO2 concentration in blood, more CO2 is converted to carbonic acid and further to bicarbonate. I thought that increased CO2 led to a decrease in pH (Bohr shift). And the effect of temperature. Could it just be that O2 dissolves more easily in a cold medium? does temperature play a role in hemoglobin affinity for oxygen?

My last question is: What's the difference in the blood O2 dissociaton curve between large and small mammals? what is the physiological consequences by this difference?

Answers are highly appreciated! Thanks:)