A Level Biology Practice Exam

Why is the presence of oxyhaemoglobin important for cellular respiration?

1. It increases the acidity of blood, facilitating oxygen release

2. It allows for efficient transport of oxygen from lungs to tissues

3. It binds carbon dioxide more effectively than unbound haemoglobin

4. It prevents oxygen from being released into the bloodstream

The correct answer is: It allows for efficient transport of oxygen from lungs to tissues

The importance of oxyhaemoglobin in cellular respiration primarily lies in its role in the efficient transport of oxygen from the lungs to the tissues. Oxyhaemoglobin is formed when oxygen binds to haemoglobin in red blood cells during respiration in the lungs. This process not only allows for a significant increase in the amount of oxygen transported in the blood compared to if it were dissolved alone but also ensures that oxygen can be delivered effectively where it’s needed, specifically to tissues that are metabolically active and require oxygen for processes such as aerobic respiration. When oxygen is released from oxyhaemoglobin in tissues, it is readily available for diffusion into cells, where it is used to produce ATP through cellular respiration. The binding and release of oxygen are also influenced by conditions such as pH and temperature, enabling more oxygen to be released in areas where it is most needed, such as actively respiring tissues that generate carbon dioxide and heat. This adaptability and efficiency underscore the critical importance of oxyhaemoglobin in sustaining metabolic processes in living organisms.