For each situation, say whether the oxygen dissociation curve shifts to the right or to the left…
Contributed by StemPy LabTry it on paper first. A hint, the key idea and the worked solution are here when you need them.
For each situation, say whether the oxygen dissociation curve shifts to the right or to the left, and whether oxygen is released more easily or less easily.
- A leg muscle during a hard run.
- Cold blood in the fingers on a freezing day.
- Blood with a higher hydrogen ion concentration, that is a lower pH.
- Blood with a lower pCO in the alveoli.
- A person with a high fever.
Need a reminder? The key ideaShow
The oxygen dissociation curve is S-shaped. At mm Hg haemoglobin is about per cent saturated, and at mm Hg about per cent. A higher pCO, more hydrogen ions or a higher temperature shift it to the right, and oxygen is released more easily.
The worked solution
Have you tried it?
Work it out on paper first. It is fine to get stuck or make a mistake: that is how we learn. When you are ready, go through the solution one step at a time, and check each step against your own.
Step 1. (a) The muscle makes carbon dioxide and heat and hydrogen ions, so the curve shifts to the right. Oxygen is released more easily.
Step 2. (b) Cold blood has a lower temperature, so the curve shifts to the left. Oxygen is released less easily.
Step 3. (c) More hydrogen ions shift the curve to the right. Oxygen is released more easily.
Step 4. (d) A lower pCO shifts the curve to the left, so the haemoglobin holds oxygen tightly, as it should in the alveoli.
Step 5. (e) A high temperature shifts the curve to the right. Oxygen is released more easily.
Answer: (a) right; (b) left; (c) right; (d) left; (e) right.
Watch out. Right does not mean that haemoglobin holds more oxygen. It means that it lets go more easily.
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