Question

In what form is the majority of carbon dioxide transported in the blood? a. Bicarbonate ion b. Carbaminohemoglobin c. Carbonic acid d. Carbonic an hydrase

Short answer

Answer: Bicarbonate ion

Step-by-step solution

Understand the options

The four options provided are different forms of carbon dioxide transport in the blood. Let's briefly understand each: a. Bicarbonate ion (HCO3-) is formed when CO2 combines with water (H2O) in the presence of the enzyme carbonic anhydrase. It is a major form of CO2 transport in the blood. b. Carbaminohemoglobin is formed when CO2 reacts with hemoglobin, binding directly to it in the blood. c. Carbonic acid (H2CO3) is formed when CO2 combines with water, but it is an unstable intermediate form that quickly dissociates into bicarbonate ions (HCO3-) and hydrogen ions (H+). d. Carbonic anhydrase is an enzyme found in red blood cells that catalyzes the formation of carbonic acid from CO2 and water, which then dissociates into bicarbonate ions and hydrogen ions.

Identify the most prevalent form

Given the information above, we can deduce that the majority of carbon dioxide is transported in the blood as bicarbonate ions (HCO3-). Bicarbonate ions account for up to 70% of the total CO2 transport in the blood. Carbaminohemoglobin and carbonic acid account for smaller percentages, and carbonic anhydrase is an enzyme involved in the process, but is not a form of CO2 transport itself.

Select the correct answer

Therefore, based on the information provided, the correct answer is: a. Bicarbonate ion