Neco Model Questions Vol1 2018 Biology Question 4

Practice essay / theory question 4 from the 2018 Neco Model Questions Vol1 Biology examination. This question covers respiration .

Neco Model Questions Vol1 2018 Biology Essay / Theory
Topic: respiration
Question 4 NECO_MODEL_QUESTIONS_VOL1 • 2018 • BIOLOGY • essay

The diagram shows the major structures of the human respiratory system.

Question Parts

( a )
Identify the structure where external gas exchange occurs. Describe at least three structural adaptations of this structure that enhance the efficiency of diffusion of gases.
( b )
Assuming each alveolus is a perfect sphere with a mean diameter of 0.2 mm and that an adult human has 480 million alveoli, estimate the total surface area available for gas exchange. Take into account that only 70 % of the alveolar surface is effectively available because of surfactant coating. Show all steps and give your answer in square metres (m²) to two significant figures.
( c )
Using the diagram, explain how the partial pressure gradients of oxygen (O₂) and carbon dioxide (CO₂) are established and maintained during a normal resting breath.
( d )
Briefly discuss the physiological response of the respiratory centre to a sudden decrease in atmospheric PO₂ (as experienced at high altitude). Include the role of chemoreceptors and the resulting change in breathing pattern.

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About This Question

This is Neco Model Questions Vol1 2018 Biology Question 4. It is one of the essay questions from the 2018 Neco Model Questions Vol1 Biology examination.

The question covers respiration .

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