role of haemoglobin and oxygen dissociation Flashcards
enrtyrocytes
red bood cells
molecule of haemoglobin
4 haem group
each are able to bond to one molecule of oxygen
oxygen + haemoglobin
oxyhaemoglobin
how is carbon dioxide transported through the body
- dissolves in blood plasma
- bind to haemoglobin forming carbaminohaemoglobin
- transported in the form fo HCO3-
how are hydrogen carbonate ions formed
when co2 diffuses into red bloof cells, it combines with water
what catalyses the reaction between carbon dioxide and water
carbonic anhydrase, which is found in red blood cells
why does the pH of blood lower sometimes
carbonic acid dissociated into H+ and HCO3- ions lowering the pH
what prevents H+ ions from lowering the pH
H+ ions combine with haemoglobin to form haemoglobinic acid
oxygen dissociation curve
shows the rate at which oxygen associates with haemoglobin at different partial pressures of oxygen
partial pressure of oxygen
the pressure exerted by oxygen within a mixture of gases
- measure of O2 concentration
when is haemoglobin referred to as saturated
when all of its oxygen binding sites are taken u with oxygen
high affinity haemoglobin
binds easily and dissociates slowly
low affinity haemoglobin
binds slowly with oxygen and dissociates easily
why is the oxygen dissociation curve of haemoglobin s shapes
it reflects the difficulty of binding the first oyxgen molecule, followed by easier binding of the next molecules due to cooperative binding
why is the curve shallow at the bottom left of the graph
the first oxygen molecule binds slowly because the haemoglobins shape makes initial binding difficult
what happens to haemoglobin after the first oxygen molecule binds
haemoglobin changes shape (conformation) which makes it easier for additional oxygen molecules to bind
what is cooperative binding in haemoglobin
a process where oxygen binding causes a change in shape in haemoglobin, making it easier for more oxygen to bind
why does the oxygen dissociation curve level off at the top right
few binding sites are available, making it harder for the fourth oxygen molecule to bind
why does haemoglobin bind oxygen slowly at low pO2
Haemoglobin has a low affinity for oxygen at low pO2, so saturation remains low
why does haemoglobin bind oxygen easily at high pO2
Haemoglobin has a high affinity for oxygen, allowing it to become more saturated as blood passes through the lungs
bohr effect
the shift in the oxygen dissociation curve due to changes in carbon dioxide levels
how does high co2 affect haemoglobins affinity for oxygen
haemoglobins affinity for oxygen decreases, making it release oxygen more easily
why does high co2 lower haemoglobins oxygen affinity
co2 lowers blood pH by forming carbonic acid, which dissociates into hydrogen ions
why is the bohr effect beneificial for respiring tissues
it ensures that oxygen is released where its needed most
how does the bohr effect appear on an oxygen dissociation curve
the curve shifts to the right when co2 levels increase
haemoglobin of a developing foetus
has higher affinity for oxygen than adults to obtain oxygen from mothers blood
