In a model lung, ventilation stops but blood initially continues to flow. Oxygen continues to enter the blood and carbon dioxide continues to enter the alveolar air.
Which changes are expected as the same air remains in the alveoli?
The oxygen gradient increases and the carbon dioxide gradient decreases.
The oxygen gradient decreases and the carbon dioxide gradient decreases.
The oxygen gradient decreases and the carbon dioxide gradient increases.
The oxygen gradient increases and the carbon dioxide gradient increases.
42 exam-style questions on Edexcel GCSE Biology 8.1 Exchange surfaces and diffusion, covering 8.1.1 Introduction to exchange and transport, 8.1.2 Alveoli adapted for gas exchange, 8.1.3 Factors affecting rate of diffusion, and 8.1.4 Rate of diffusion using Fick's law. Each one has a worked solution and a mark scheme showing where the marks go.