Question

Smoking increases oxygen deficiency in the body because

Answer 1

Smoking tobacco leaves for pleasure has been a human habit for hundreds of years in spite of the fact that smoking takes a heavy toll on our health. The smoke produced from burning tobacco contains around 7000 different chemical compounds including tar (solid particles suspended in tobacco smoke), nicotine, carbon monoxide, 70 different types of carcinogens (compounds which can cause cancer), etc.

Nicotine is the major stimulating and highly addictive component of all tobacco products but the carbon monoxide present in the tobacco smoke has serious ill effects too.

Carbon monoxide is a gas that is usually released due to incomplete combustion of a substance in limited supply of oxygen. It is a highly poisonous gas which can be fatal when inhaled in high concentrations.

Carbon monoxide gas has a high affinity for the haemoglobin present in our red blood cells. Upon inhalation, it readily binds with the haemoglobin to form a stable compound named carboxyhaemoglobin. This compound does not readily dissociate unlike oxyhaemoglobin (formed when oxygen combines with haemoglobin) or carbamino haemoglobin (formed when carbon dioxide combines with haemoglobin).

In normal conditions, oxygen carried by the blood from the lungs to the tissues is transported as oxyhaemoglobin which is an unstable compound. On reaching the tissues, which have a low concentration of oxygen, the oxyhaemoglobin dissociates to release oxygen which is taken up by the tissues and utilised for aerobic respiration. As more and more haemoglobin combines irreversibly with carbon monoxide, the ability of haemoglobin to bind and transport oxygen to the tissues decreases. This creates oxygen deficiency in the tissues of cigarette smokers. Oxygen is needed by cells for aerobic respiration. Its deficiency in the tissues causes malfunctioning in the body such as dizziness, shortness of breath, headache and loss of brain activity.

The inhaled smoke does not destroy the red blood cells nor breaks down the haemoglobin present in the blood.

Hence, option b is correct.