transport of oxygen Flashcards
what is haemoglobin
the red pigment used to transport thee oxygen in the blood.
what is association
the binding of two molecules, commonly used in biology when referring to the bonding of oxygen onto haemoglobin
why can haemoglobin transport oxygen
because the reaction is reversible- the reverse reaction is called dissociation so that oxygen can be used in respiration.
whats dissociation
the separation of two molecules, used in biology when referring to the unloading of oxygen from haemoglobin
binding of the first o2 molecule causes a…
conformational change in the haemoglobin molecule
what does the conformational change do
the conformational change makes the haem groups more accessible to oxygen
why is the gradient of the graph initially shallow on the oxygen dissociation graph
cus the haem groups are all unbound and held tightly within the haemoglobin
once the first haem group binds…
positive cooperativity causes the gradient to increase steeply
why does the curve plateau
cus its less likely for an oxygen molecule to collide with the last empty site on each haemoglobin molecule
talk about foetal haemoglobin
has a higher affinity for oxygen than adult haemoglobin to ensure it gains enough oxygen
talk about animals living at a high altitude and their haemoglobin
animals that live at high altitude have a higher affinity for o2 than those that live at lower altitudes
what is co2 released from and transported by
co2 is released from respiring tissues and transported by the blood to lungs for excretion
5% of CO2 …
transported is dissolved in the blood plasma
10% of co2…
transported is combined with haemoglobin to form carbaminohaemoglobin
CO2+Hb carbaminohaemoglobin
85% of co2…
is transported as hydrogen carbonate ions dissolved in blood plasma (HCO3-)
talk about the formation of hydrogen carbonate (HCO3-)
- CO2 diffuses into red blood cells and combines with water to form carbonic acid (H2CO3)
- carbonic acid dissociates (splits up) to form hydrogen carbonate and a hydrogen ion. H2CO3H+ + HCO3-
where does hydrogen carbonate go after diffusing out the cell
its transported around the body to the lungs
what happens when HCO3 leaves the cell a lot
it causes the cell to become positive which is bad as they need to maintain charge
how does a cell rebalance when HCO3 leaves the cell
chloride ions diffuse in to balance the charge from the loss of hydrogen carbonate ions- this is called the chloride shift
what is the chloride shift
the movement of chloride ions into the erythrocytes to balance the charge as hydrogen carbonate ions leave the cell
what can haemoglobin act as
haemoglobin acts as a buffer by taking up the hydrogen ions produced by the dissociation of carbonic acid
what effect does co2 have on haemoglobin
has an effect on the ability of haemoglobin to transport oxygen
whats the bhor effect
the effect that increasing co2 concentration has on haemoglobin explaining how oxygen is released where its needed
its important that at the lungs:_________
but at the tissues:________
at the lungs: oxygen is taken onto haemoglobin
but at the tissues: oxygen can be released and co2 to join
what happens when co2 dissolves in the cytoplasm
when it dissolves in the cytoplasm of red blood cells to form carbonic acid which dissociates to produce H+, co2 then combines with water forming carbonic acid- carbonic acid then dissociates into H+ and hydrogen carbonate
what do H+ ions do for haemoglobin
lower the pH of the cytoplasm which affects the tertiary structure of haemoglobin
then
haemoglobin affinity for oxygen is reduced at lower pH and so oxygen is reduced at lower pH and so oxygen is unloaded in respiring tissues
respiring tissues produce CO2 causing…
causing HCO3- to form and H+»_space; makes haemoglobin release O2 to tissue. lowers affinity- cells use it for respiration
