Identify the correct statement with reference to transport of respiratory gases by blood.

Options

A. Haemoglobin is necessary for transport of carbon dioxide and carbonic anhydrase for transport of oxygen.
B. Haemoglobin is necessary for transport of oxygen and carbonic anhydrase for transport of carbon dioxide.
C. Only oxygen is transported by blood.
D. Only carbon dioxide is transported by blood.

Answer

To identify the correct statement regarding the transport of respiratory gases by blood, let's analyze the information step by step:

### Step 1: Understand the Role of Hemoglobin
- Hemoglobin is a protein found in red blood cells that primarily binds to oxygen. It is essential for transporting oxygen from the lungs to the tissues in the body.

### Step 2: Understand the Role of Carbonic Anhydrase
- Carbonic anhydrase is an enzyme that facilitates the conversion of carbon dioxide (CO2) and water (H2O) into carbonic acid (H2CO3). This reaction is crucial for the transport of carbon dioxide in the blood.

### Step 3: Analyze the Statements
- The first statement claims that hemoglobin is necessary for the transport of carbon dioxide and carbonic anhydrase for the transport of oxygen. This is incorrect because hemoglobin is primarily responsible for oxygen transport, while carbonic anhydrase aids in carbon dioxide transport.

- The second statement indicates that hemoglobin is necessary for the transport of oxygen and carbonic anhydrase for the transport of carbon dioxide. This is correct as hemoglobin indeed transports oxygen and carbonic anhydrase plays a role in the transport of carbon dioxide.

### Step 4: Conclusion
- Based on the analysis, the correct statement is: "Hemoglobin is necessary for the transport of oxygen and carbonic anhydrase for the transport of carbon dioxide."