Question

When red blood cells transport respiratory gases, which of the following is true?

1) Both oxygen and carbon dioxide combine to the globin portion.
2) Carbon dioxide binds to the heme portion and oxygen binds to the globin portion.
3) Both oxygen and carbon dioxide combine to the heme portion.
4) Oxygen binds to the heme portion while carbon dioxide binds to the globin portion.

Answer 1

In red blood cells, hemoglobin transports oxygen and carbon dioxide. Oxygen binds to the iron ions in hemoglobin, forming oxyhemoglobin, while carbon dioxide can bind to hemoglobin, forming carbaminohemoglobin. Hemoglobin releases oxygen in the body tissues and releases carbon dioxide in the lungs.

Step-by-step explanation:

In red blood cells, oxygen and carbon dioxide are transported by the protein hemoglobin. When oxygen binds to the iron ions in hemoglobin, it forms oxyhemoglobin, which is bright red in color. As hemoglobin travels to body tissues, it releases some oxygen molecules, becoming darker red deoxyhemoglobin. Carbon dioxide enters the bloodstream and can bind to hemoglobin, forming carbaminohemoglobin. When hemoglobin returns to the lungs, it releases carbon dioxide for exchange with oxygen.