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Examine the following table - VCE - SSCE Biology - Question 5 - 2006 - Paper 1
Question 5
Examine the following table. Summary carbon dioxide and oxygen levels in air and water Chemical Solubility in water Concentration in air Oxygen ... show full transcript
Worked Solution & Example Answer:Examine the following table - VCE - SSCE Biology - Question 5 - 2006 - Paper 1
Step 1
Why are mammals more susceptible to a build-up of carbon dioxide than fish?
Answer
Mammals are more susceptible to a build-up of carbon dioxide than fish because they primarily rely on lungs for gas exchange. This means they are more affected by fluctuations in carbon dioxide levels, which can lead to a decrease in blood pH. Fish, on the other hand, can regulate CO₂ levels efficiently through gills, allowing better adaptation to changes in water and gas concentrations.
Step 2
Consider a mammal that experiences an increase in its blood pH. Name one effector and suggest what its response would be?
Answer
One effector in this scenario could be the respiratory system. If a mammal experiences an increase in blood pH (signifying a decrease in CO₂), the response would be to decrease the breathing rate, allowing more CO₂ to accumulate in the blood, thereby restoring the normal pH balance.
Step 3
Explain why underwater pearl divers, who use no special diving apparatus, would hyperventilate.
Answer
Underwater pearl divers hyperventilate to increase oxygen intake and reduce carbon dioxide levels in the blood before diving. This can help extend their time underwater since lower CO₂ levels can delay the urge to breathe, allowing for longer dives without immediate discomfort.
Step 4
Why does hyperventilation cause a person to become unconscious?
Answer
Hyperventilation causes a person to become unconscious due to a rapid decrease in carbon dioxide levels, leading to respiratory alkalosis. This can cause cerebral vasoconstriction, reducing blood flow to the brain, which may result in dizziness, fainting, or loss of consciousness.