A Level Biology Practice Exam

What is the definition of oxyhaemoglobin?

1. A type of haemoglobin that is saturated with carbon dioxide

2. A molecule of haemoglobin with oxygen molecules loosely bound to it

3. Hemoglobin that has been denatured due to high temperatures

4. A blood component that transports nutrients throughout the body

The correct answer is: A molecule of haemoglobin with oxygen molecules loosely bound to it

The definition of oxyhaemoglobin is accurately described as a molecule of haemoglobin with oxygen molecules loosely bound to it. This form of haemoglobin is critical for the respiratory process in vertebrates, as it enables the efficient transport of oxygen from the lungs to the body's tissues. When oxygen enters the bloodstream in the lungs, it binds to the iron-containing heme groups in the haemoglobin molecule. The binding is reversible, allowing oxyhaemoglobin to release oxygen in areas where it is needed, such as metabolically active tissues. This reversible binding is key to maintaining homeostasis and ensuring that tissues receive adequate oxygen for cellular respiration. The other definitions provided do not accurately represent oxyhaemoglobin. Oxyhaemoglobin specifically refers to the form of haemoglobin associated with oxygen, not carbon dioxide, nor does it imply any condition such as denaturation or a role in nutrient transportation.