bio 1500 test 5
1. connect molecular changes during O2 binding to cooperative O2 binding
properties of Hb: as more O2 binds it changes the shape so the O2 binds more eflciently
2. relate the O2-Hb dissociation curve to the partial O2 pressure in lung and
body and explain the advantage of its sigmoidal shape.: - In the lung close to 100% for
wide range of PO2
- In the body: steep part of sigmoid (big change when PO2 drops)
- At normal body PO2 hemoglobin keeps 70-80% of oxygen
3. Explain how the O2 affinity of Hb decreases in the body, incl. which factors
contribute to this decrease and how this facilitates the release of O2 in the
body.: - Aflnity decreases in the body
- PCO2 increases causes a right shift (lower aflnity)
- pH decreases causes a right shift
- 2,3BPG increases causes a right shift
- Temperature increases causes a right shift
1/5
, - In the body compared to the lungs: PCO2 is increases pH decreased higher temperature all these factors cause a right
shift in the curve
- oxygen aflnity of hemoglobin changes in the lungs: aflnity is high in the body: temp increases, PCO2 increases, pH
decreases so changes to a low aflnity (right shift) back in the lungs temp and PCO2 decreased and pH increas es and
changes to high aflnity (left shift)
4. summarize how pH, PCO2, temperature, and 2,3-BPG change the tertiary
and quaternary structure of Hb and thus its O2 affinity.: - CO2, H+, and 2, 3-BPG are
charged/polar
- They attach to charged amino acids on the outside of Hb subunits
- Changes tertiary and quaternary structure of Hb (changes function, changed by changing the charges on the outside)
- Changing a single amino acid could change function of a protein
5. explain why human Hb does not work sufficiently at high altitude, by relating
PO2 at low and high altitude to the O2 Hb dissociation curve.: - At high altitudes PO2 is
lower which means there's less PO2 in the lungs and a smaller % of Hb with O2 in the lungs
- This is the difference of scaling on Mt Everest is more strongly caused by the inability to bind suflcient O2o in the
lungs
- O2 carrying capacity is reduced by 1/3
- Above 6,000m PO2 is too low to effectively load Hb with O2 to allow sustained work
2/5
1. connect molecular changes during O2 binding to cooperative O2 binding
properties of Hb: as more O2 binds it changes the shape so the O2 binds more eflciently
2. relate the O2-Hb dissociation curve to the partial O2 pressure in lung and
body and explain the advantage of its sigmoidal shape.: - In the lung close to 100% for
wide range of PO2
- In the body: steep part of sigmoid (big change when PO2 drops)
- At normal body PO2 hemoglobin keeps 70-80% of oxygen
3. Explain how the O2 affinity of Hb decreases in the body, incl. which factors
contribute to this decrease and how this facilitates the release of O2 in the
body.: - Aflnity decreases in the body
- PCO2 increases causes a right shift (lower aflnity)
- pH decreases causes a right shift
- 2,3BPG increases causes a right shift
- Temperature increases causes a right shift
1/5
, - In the body compared to the lungs: PCO2 is increases pH decreased higher temperature all these factors cause a right
shift in the curve
- oxygen aflnity of hemoglobin changes in the lungs: aflnity is high in the body: temp increases, PCO2 increases, pH
decreases so changes to a low aflnity (right shift) back in the lungs temp and PCO2 decreased and pH increas es and
changes to high aflnity (left shift)
4. summarize how pH, PCO2, temperature, and 2,3-BPG change the tertiary
and quaternary structure of Hb and thus its O2 affinity.: - CO2, H+, and 2, 3-BPG are
charged/polar
- They attach to charged amino acids on the outside of Hb subunits
- Changes tertiary and quaternary structure of Hb (changes function, changed by changing the charges on the outside)
- Changing a single amino acid could change function of a protein
5. explain why human Hb does not work sufficiently at high altitude, by relating
PO2 at low and high altitude to the O2 Hb dissociation curve.: - At high altitudes PO2 is
lower which means there's less PO2 in the lungs and a smaller % of Hb with O2 in the lungs
- This is the difference of scaling on Mt Everest is more strongly caused by the inability to bind suflcient O2o in the
lungs
- O2 carrying capacity is reduced by 1/3
- Above 6,000m PO2 is too low to effectively load Hb with O2 to allow sustained work
2/5
