Waec Model Questions Vol1 2025 Biology Question 5

Practice objective / multiple choice question 5 from the 2025 Waec Model Questions Vol1 Biology examination.

Waec Model Questions Vol1 2025 Biology Objective / Multiple Choice Medium Difficulty
Question 5 WAEC_MODEL_QUESTIONS_VOL1 • 2025 • BIOLOGY • objective

Using the alveolar gas equation PAO₂ = FiO₂ (Patm - PH₂O) - PaCO₂ ⁄ R, calculate the alveolar partial pressure of oxygen (PAO₂) for a healthy adult at sea level (Patm = 760 mmHg) and again at an altitude where Patm = 600 mmHg. Assume FiO₂ = 0.21, PH₂O = 47 mmHg, arterial CO₂ pressure PaCO₂ = 40 mmHg and respiratory quotient R = 0.8. Give your answers to the nearest whole mmHg.

Answer Options

A. Sea‑level PAO₂ ≈ 95 mmHg; at 600 mmHg Patm, PAO₂ ≈ 60 mmHg
B. Sea‑level PAO₂ ≈ 105 mmHg; at 600 mmHg Patm, PAO₂ ≈ 70 mmHg
C. Sea‑level PAO₂ ≈ 90 mmHg; at 600 mmHg Patm, PAO₂ ≈ 55 mmHg
Correct Answer D. Sea‑level PAO₂ ≈ 100 mmHg; at 600 mmHg Patm, PAO₂ ≈ 66 mmHg
Correct Answer
D
Correct Option:
Sea‑level PAO₂ ≈ 100 mmHg; at 600 mmHg Patm, PAO₂ ≈ 66 mmHg

About This Question

This is Waec Model Questions Vol1 2025 Biology Question 5. It is one of the objective questions from the 2025 Waec Model Questions Vol1 Biology examination.

Difficulty level: Medium .

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