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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 | |----------... show full transcript
Worked Solution & Example Answer:Examine the following table - VCE - SSCE Biology - Question 5 - 2006 - Paper 1
Step 1
a. 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 primarily due to their respiratory physiology. Fish have specialized adaptations like gills that effectively extract oxygen from water and efficiently eliminate carbon dioxide. Mammals, on the other hand, rely on lungs for gas exchange, which is less efficient in expelling carbon dioxide. Moreover, mammals have a greater metabolic rate and thus produce more carbon dioxide, increasing the likelihood of accumulation in the bloodstream.
Step 2
b. 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 response to an increase in blood pH is the respiratory system. The mammal would increase its breathing rate to eliminate excess carbon dioxide. This helps lower blood pH back to its normal range, as more carbon dioxide exhaled reduces the pH level.
Step 3
c. Explain why underwater pearl divers, who use no special diving apparatus, would hyperventilate.
Answer
Underwater pearl divers hyperventilate to quickly expel carbon dioxide from their bodies. This action raises their blood oxygen levels and delays the onset of hypoxia while submerged. By increasing the oxygen supply and reducing carbon dioxide buildup, divers can extend the duration they can hold their breath and stay underwater without unconsciousness.
Step 4
d. Why does hyperventilation cause a person to become unconscious?
Answer
Hyperventilation causes a reduction in carbon dioxide levels in the blood, leading to respiratory alkalosis, which can cause symptoms such as dizziness, tingling, and fainting. The drastic decrease in carbon dioxide reduces cerebral blood flow, which can cause loss of consciousness. Additionally, the brain’s receptors may trigger a response to the altered blood chemistry, further contributing to unconsciousness.