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secondary 3 | Biology
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chubbun
Chubbun

secondary 3 chevron_right Biology

help!

Date Posted: 6 years ago
Views: 414
Ng Yeng Ting
Ng Yeng Ting
6 years ago
Think in terms of gaseous exchange in the lungs. In order for CO2 to be exhaled, concentration of O2 in atmosphere is higher and CO2 diffuses from blood into the alveoli and O2 diffuses from alveoli into blood.
Too much O2 in the Long term is harmful is because of O2 radical damage to lungs and also gas flow across alveoli slows down.

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Arnold K H Tan
Arnold K H Tan's answer
2155 answers (A Helpful Person)
1st
Note that under the old syllabus, you had to know that exhaled aor contained 4% CO2, 16% O2, the rest being mainly N2. If gas A were used (common mistake as a choice), there would be a net diffusion of both O2 and CO2 into the blood... but excess CO2 in blood can result in lowering blood pH to toxic levels.
chubbun
Chubbun
6 years ago
thank you
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Arnold K H Tan
Arnold K H Tan's answer
2155 answers (A Helpful Person)
Read this and choose any suitable point for part c).