When i asked my monoxide...they told that.. .. Hemoglobin is an iron-containing oxygen transport metalloprotein in the red blood cells of most mammals. Simply put, it's a carrier protein. Interestingly it doesn't carry carbon dioxide in the same way it does for oxygen $\ce{O2}$. Oxygen binds to the iron atoms in the protein whereas carbon dioxide $\ce{CO2}$ is bound to the protein chains of the structure. Carbon dioxide doesn't compete with oxygen in this binding process. However, carbon monoxide $\ce{CO}$ is a very aggressive molecule. It's a colourless, odourless, and tasteless gas that is lighter than air and can be fatal to life. It has a greater affinity for hemoglobin than oxygen does. It displaces oxygen and quickly binds, so very little oxygen is transported through the body cells.

Introduction:
Carbon monoxide (CO) and oxygen (O2) are both gases that can bind to hemoglobin (Hb) in the blood. Hemoglobin is responsible for transporting oxygen to the body's tissues. However, carbon monoxide has a greater affinity for hemoglobin compared to oxygen.

Affinity of Carbon Monoxide for Hemoglobin:
Carbon monoxide has a higher affinity for hemoglobin because of its stronger binding to the heme group in hemoglobin. The heme group is a component of hemoglobin that can bind to oxygen molecules.

Comparison with Oxygen:
To understand the affinity difference, let's compare the binding characteristics of carbon monoxide and oxygen to hemoglobin.

1. Affinity:
- Carbon monoxide: Carbon monoxide binds to heme with a higher affinity.
- Oxygen: Oxygen binds to heme with a lower affinity.

2. Stability of Complexes:
- Carbon monoxide: The complex formed between carbon monoxide and heme is highly stable.
- Oxygen: The complex formed between oxygen and heme is less stable.

3. Dissociation:
- Carbon monoxide: Carbon monoxide has a slower dissociation rate from hemoglobin.
- Oxygen: Oxygen has a faster dissociation rate from hemoglobin.

Effect on Oxygen Transport:
Due to the higher affinity of carbon monoxide for hemoglobin, it can outcompete oxygen for binding sites on hemoglobin. This means that when carbon monoxide is present in the blood, it can bind to hemoglobin and prevent the binding of oxygen.

This has serious implications for oxygen transport in the body. If carbon monoxide levels are high, it can lead to carbon monoxide poisoning, where oxygen delivery to tissues is severely compromised. This can result in symptoms such as dizziness, headache, confusion, and even death if not treated promptly.

Conclusion:
In conclusion, carbon monoxide has a greater affinity for hemoglobin compared to oxygen. Its stronger binding to hemoglobin and slower dissociation rate make it a potent competitor for oxygen binding sites. Understanding this affinity difference is crucial for recognizing the dangers of carbon monoxide poisoning and taking appropriate preventive measures.