Effect of increasing carbon dioxide concentration Flashcards
Effect of increasing carbon dioxide concentration
The pO2 in respiring tissue is lower than in the lungs as O2 has been used in aerobic respiration. As a result oxyhaemoglobin begins to dissociate, meaning it is available to bind with H+ to form haemoglobinic acid.
Bohr effect: the effect extra CO2 has on haemoglobin, explaining the release of more O2.
- CO2 enters red blood cells forming carbonic acid, which dissociates to release H+ ions.
- These hydrogen ions affect the cytoplasm, making it more acidic.
- The change in pH affects the tertiary structure of haemoglobin. The increased acidity causes a
conformational change, reducing the affinity of haemoglobin for oxygen.
- The haemoglobin is unable to hold as much O2, and O2 is released from oxyhaemoglobin to tissues.
Here tissues, such as contracting muscles, are respiring more, there will be more carbon dioxide. As a result more hydrogen ions will be produced in red blood cells, making the
oxyhaemoglobin release more oxygen.
The Bohr effect results in more oxygen being released where more carbon
dioxide is produced in respiration, this is what muscles need to continue respiring aerobically.
When more carbon dioxide is present, haemoglobin becomes less saturated with oxygen, this causes the haemoglobin dissociation curve to shift down to the right – Bohr shift.
