What poisonous gas is present in cigarette smoke that binds to hemoglobin? Why is it dangerous?

What will be an ideal response?


Carbon monoxide (CO). It is dangerous because inhaled CO interferes with gas exchange. It binds to hemoglobin and therefore blocks sites that would otherwise bind oxygen. Hemoglobin binds to CO more than 200 times more tightly than oxygen. In addition, binding of CO also makes hemoglobin hold more tightly to any oxygen that it does bind. Thus, when CO is present, blood holds less oxygen and delivers less of what it does have to tissues.

Smoking cigarettes increases blood CO-bound hemoglobin by about 5 percent for each pack smoked per day. Over the short term, a blood CO-bound hemoglobin level as low as 4–6 percent can decrease a healthy young person's capacity to exercise. Over the longer term, an increased CO-bound hemoglobin level harms the heart, which must work overtime to make up for CO's suffocating effects on respiratory function.

Biology & Microbiology

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such as ____.

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Fill in the blank(s) with correct word

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If the haploid number of an organism is 6, the diploid number will be 

A. 3. B. 6. C. 9. D. 12.

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