Question

1. According to the ideal gas law (also called the general gas equation), how does temperature affect the partial pressure of O2 in air?

2. How does temperature affect the partial pressure of O2 in water?

3. How does pH affect the partial pressure of O2 in water?

4. Please give examples of animals that use cocurrent, countercurrent, and cross-current gas exchange.

Answer 1

1) According to the ideal gas law, i.e., the general gas equation, PV = nRT, where,

P = partial pressure of gas

V = volume of gas

n = number of moles of gas

R = gas constant

T = absolute temperature, i.e., temperature in kelvin

Therefore, according to this equation, Partial pressure and Absolute temperature have a direct relationship with each other, hence, the lower the temperature, i.e., colder the air, the less partial pressure O2 has in the air.

2) In water, partial pressure of O2 is dependent upon solubility of O2 in water and Oxygen solubility is strongly temperature dependent and decreases at higher temperatures.

4) Animals using counter-current gas exchange : all fish using gills (bony fish), chondrichtyans

Animals using cross- current flow : Birds