3.2 Haemoglobin & CO2 transport Flashcards
What type of molecule is haemoglobin?
Conjugated protein with a haem group - 4 polypeptide chains
Haemoglobin is found where?
In RBCs
Haemoglobin bings to what?
Oxygen
What is the role of Haemoglobin?
To transport oxygen around the body
To be efficient what must Haemoglobin do?
Readily associate with oxygen at exchange surfaces
Readily dissociate from oxygen when tissues need it
What is it called when oxygen and Haemoglobin bind?
Oxyhaemoglobin
What are the two types of Haemoglobin?
Haemoglobin with high affinity for oxygen
Haemoglobin with low affinity for oxygen
Haemoglobin with high affinity for oxygen does what?
Takes oxygen up easily
Hard to release
Haemoglobin with a low affinity for oxygen does what?
Takes it up less easily
Releases it readily
What is loading or associating?
The process of oxygen combining with Haemoglobin at exchange surfaces
What is unloading or dissociating?
Oxygen released
At low concentrations of oxygen what is it difficult to do?
Absorb oxygen
Once the first oxygen is loaded what do the remaining 3 molecules do?
Load easily
The further to the left the higher the what?
Affinity for oxygen
Where is myoglobin found?
In muscle
What does myoglobin have/do?
High affinity for oxygen
One haem group
Acts as oxygen reserve
When carbon dioxide diffuses into bloodstream what does 10-20% do?
Binds to amine groups forming carbaminohaemoglobin
75-85% of carbon dioxide is converted into what?
Hydrogen carbonate by carbonic anhydrase
H2CO3 dissociates into what?
H+
HCO3-
The HCO3- moves out of RBCs to where?
Plasma
Negatively charged chloride ions move into where?
RBCs
Why does foetal Haemoglobin have a higher affinity for oxygen?
To maximise oxygen uptake from the mothers bloodstream which has already used some up by the time it reaches the placenta
CO2 lowers Haemoglobins what?
Affinity for oxygen
Dissolved CO2 has what effect on pH and what does this do? What is this called?
Lowers PH because it is acidic
Causes proteins to change shape releasing CO2
BOHR EFFECT
The Bohr effect is important to provide what?
Necessary for providing oxygen to active tissues readily
Oxygen binding easily in lungs
At gas exchange surfaces what is removed?
CO2
Low levels of CO2 increases what?
PH
High pH changes what?
Haemoglobin so oxygen loads readily - increased affinity
In tissues where CO2 is made, pH decreases so what happens?
Haemoglobin changes shape
Lowers affinity for O2
So it is unloaded into respiring tissues
