Haemoglobin Flashcards
Describe how haemoglobin normally loads oxygen in the lungs and unloads it in a tissue cell.
- Oxygen combines (reversibly) to produce oxyhaemoglobin
- Each haemoglobin molecule/one haemoglobin may transport 4 molecules of oxygen
- High partial pressure of oxygen/concentration in lungs
- Haemoglobin (almost) 95%/100% saturated
- Unloads at low oxygen tension (in tissues)
- Presence of carbon dioxide displaces curve further to right/increases oxygen dissociation
- Allows more O2 to be unloaded
- Increase temp/acidity allows more O2 to be unloaded
- Low pO2/increase CO2/increase term/increase acid occur in vicinity of respiring tissue
Explain how oxygen in a red blood cell is made available for respiration in active tissues.
-CO2 (increased) respiration
-(increased) dissociation oxygen from haemoglobin
-Low partial pressure in tissues/plasma
Oxygen diffuses from r.b.c. to tissues
The oxygen dissociation curve of the foetus is to the left of that for its mother. Explain the advantage of this for the foetus.
- Higher affinity/loads more oxygen
- At low/same/high partial pressure/pO2
- Oxygen moves from mother/to foetus
Explain how oxygen is loaded, transported and unloaded in the blood. (6)
- Haemoglobin carries oxygen/has a high affinity for oxygen/oxyhaemoglobin
- In red blood cells
- Loading/uptake/association in lungs at high p.O2
- Unloads/dissociates/releases to respiring cells/tissues at low p.O2
- Unloading linked to higher carbon dioxide (concentration)
Binding of one molecule of oxygen to haemoglobin makes it easier for a second oxygen molecule to bind.
Explain why.
- Binding of first oxygen changes tertiary/quaternary (structure) of haemoglobin [conformational shift caused]
- Uncovers second/another binding site OR Uncovers another haem group to bind to
Describe and explain the effect of increasing carbon dioxide concentration on the dissociation of oxyhaemoglobin.
- Increases/more oxygen dissociation/unloading OR decreases haemoglobin’s affinity for O2
- (By) decreasing (blood) pH/increasing acidity