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Respiration and Gas Exchange

4 dot points across 4 inquiry questions. Click any dot point for a focused answer with worked past exam questions where available.

How do cells release energy from glucose, with and without oxygen?

Compare aerobic and anaerobic respiration and state their word equations and energy yields
A focused answer to the O-Level Biology outcome on respiration. The word equations for aerobic and anaerobic respiration in humans and yeast, the difference in energy yield, and the meaning of oxygen debt.
8 min answer →

How do the ribs and diaphragm move air into and out of the lungs?

Describe the mechanism of breathing in humans, including the role of the ribs and diaphragm
A focused answer to the O-Level Biology outcome on breathing. How the rib muscles and diaphragm change the chest volume and pressure to move air in and out, and the difference between breathing and respiration.
7 min answer →

How do exercise and smoking affect breathing and the lungs?

Explain the effects of physical activity on breathing and the harmful effects of tobacco smoke
A focused answer to the O-Level Biology outcome on exercise and smoking. Why breathing rate and depth rise during exercise, and the harmful effects of tar, nicotine and carbon monoxide in tobacco smoke.
8 min answer →

How does the human gas exchange system swap oxygen for carbon dioxide?

Describe the human gas exchange system and explain how the alveoli are adapted for gas exchange
A focused answer to the O-Level Biology outcome on human gas exchange. The path of air to the alveoli, how the alveoli are adapted for fast diffusion, and the differences between inhaled and exhaled air.
8 min answer →