Amount of O2 carried by red blood cells is:
Correct answer: D. 97%
- A. 77%
- B. 90%
- C. 87%
- D. 97%
Explanation
Red blood cells (also known as erythrocytes) contain a protein called hemoglobin, which carries oxygen from the lungs to all parts of the body. Haemoglobin is an iron-containing protein that is found within all RBCs. Haemoglobin is made of four subunits: two alpha subunits and two beta subunits. Each subunit surrounds a central heme group that contains iron and binds one oxygen molecule, allowing each hemoglobin molecule to bind four oxygen molecules, forming oxyhemoglobin. Approximately, 97% of oxygen is carried by the red blood cells as oxyhemoglobin, while 3% is transported as dissolved oxygen in the plasma.
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The human respiratory system conducts air to the alveoli, where oxygen and carbon dioxide exchange occurs across thin respiratory surfaces. Questions cover the nasal passage, trachea, bronchi, lungs, diaphragm and intercostal muscles, ventilation mechanics and gas transport, while distinguishing breathing and gaseous exchange from cellular respiration.
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