Carbon Monoxide

What is Carbon Monoxide?

A gas present in tobacco smoke that binds strongly to haemoglobin in red blood cells. Haemoglobin that has bound carbon monoxide cannot carry oxygen, so the oxygen-carrying capacity of the blood is reduced, the heart is placed under greater strain, and during pregnancy the oxygen supply to the fetus is reduced.

This definition is part of the Disease and Immunity chapter in Cambridge O Level Biology.

Concepts related to Carbon Monoxide

• haemoglobin
• oxygen transport
• fetal development

Common mistakes with Carbon Monoxide

• "Carbon monoxide destroys haemoglobin." It binds to haemoglobin. Haemoglobin that has bound carbon monoxide cannot carry oxygen, which is a different statement from being destroyed. Write Carbon monoxide binds strongly to haemoglobin, so less oxygen is transported and the heart works harder.