Biology Forums - Study Force

1.  The atmosphere is a mixture of gases.  Write the correct percentages for the following gases found in the earth’s atmosphere:

a.  O2    20.9%
b.  CO2   0.04%
c.  N2     78.6%
d.  H2O   0.46%

2.  Calculate the partial pressures of the following gases at both atmospheric pressures.

      760 mmHg        747 mmHg   
a.  O2   159mmHg        156mmHg   (760•20.9)÷100=158.84 and (747•20.9)÷100=156.12
b.  CO2   0.3mmHg         0.3mmHg   (760•0.04)÷100=0.304  and (747•0.04)÷100=0.298
c.  N2   597mmHg         587mmHg   (760•78.6)÷100=597.36 and (747•78.6)÷100=587.14
d.  H2O   3.5mmHg         3.4mmHg   (760•0.46)÷100=3.49 and (747•0.46)÷100=3.43


3.  a.  What is the atmospheric pressure on the top of Mt. Whitney?  440mmHg
     b.  Calculate partial pressure of O2 on the top of Mt. Whitney (in mmHG):  (20.9•440)÷100= 92 mmHg

4.  Why does more CO2 than O2 dissolve in liquid when both gases are the same pressure?
   a.  CO2  is more soluble in liquid than O2
   b.  Name the law that explains this phenomena:  Henry’s Law

5.  Efficient external respiration depends on three main factors, list them:
   a.  surface areas and structure of the respiratory membrane
   b.  partial pressure gradients
   c.  matching alveolar air flow to pulmonary capillary blood flow

6.  What three factors cause the partial pressures of gases in the alveoli to differ from pressure in the atmosphere?
   a.  humidification of the air
   b.  gas exchange between capillaries and alveoli
   c.  making of old and new air

7.  When airflow is restricted so that the partial pressure of O2 is low and CO2 is high, what happens to the following?
   a.  arterioles:   vasoconstriction (CO2 effect)
   b.  bronchioles:   dilation (O2 effect)



8.  Internal respiration depends on three factors, list them:
   a.  available surface area
   b.  partial pressure gradients
   c.  variable rate of blood flow varies

9.  The planet Pneumo has a total atmospheric pressure of 900mmHg.  Oxygen and Carbon Dioxide each constitute 30% of the atmosphere.

   a.  What is the partial pressure of O2  on the planet Pneumo?  (900•30)÷100= 270mmHg
   b.  Which gas would be found in the highest concentrations in your blood?  CO2

Thanks lol Just read your other post too.

You're very welcome  ;D