mass transport Flashcards
what kind of structure does haemoglobin have
quaternary
define a quaternary protein
many polypeptides bonded togteher by peptide bonds
describe the structure of haemoglobin
4 polypeptides
each polypeptide is associated with a haem group #
what does each haem group contain
Fe2+
what does the Fe2+ combine with
o2
how many O2 molecule can be carried by a single haemaglobin molecule
4
what is the process to which O2 BIND WITH HAEMAGLOBIN CALLED
association
why do different haemoglobins have different affinities for oxygen
each species produces a haemoglobin wiht a slightly different amino acid sequence. therefore each species will have a slightly different quaternary structure and therefore different oxygen binding properties .
explain oxygen dissociation curves
the initial shape of haemoglobin makes it difficult for the first oxygen to bind to the haem because they are all so close together. therefire concs are low
after the first o2 molecule has binded the haemoglobin changes shape and it akes it easier for other molecules to bind - positive cooperativity because there is a smaller change in partial pressure.
- however after the binding of the third oxygen molecule there trhe haemoglobin becomes saturated and it is now difficult ot bind because there is only one site left.
ON A GRAPH IT IS SLOW THEN INCREASES THEN PLATEAUS
how are arteries adapted for their function
thick and muscular with elastic tissue to allow stretch and recoil
how are veins adapted to their function
valves to prevent backflow and pooling
what do veins capilliaries and arteries have in common
endothelium tissue
what are some adaptations of capillaries
endothelium is only one cell thick = short diffusion pathway
large number of capillaries - increases the SA for exchange
what si the hydrostatic pressure like at the arteriole end of the capillary
higher than in the tissue fluid
what is tissue fluid
watery fluid formed from blood plasma that contains glucose, amino acids, fatty acids, ions in solution and O2
how is tissue fluid formed
at the arteriole end the hydrostatic pressure is greater than the hydrostatic pressure in the tissue fluid.
the difference in hydrostatic pressure means that fluid will be forced out of the capillaries and into the spaces to form the tissue fluid.
as fluid leaves the capillary bed the hydrostatic pressure will decrease. therefore at the venule end the hydrostatic pressure is much lower.. BTW PLASMA PROTEINS DO NOT LEAVE.
- due to fluid loss and an increasing conc in plasma proteins the water potential is lower in the venule end than in the tissue fluid therefore some water re- enters via osmosis.
what is done with excess tissue fluid
drained into the lymphatic system
how are the alveoli adapted for gas exchange
- thin exchange surface - alveolar epithelium is only one cell thick = short diffusion pathway
- large SA
which vessels carry oxygenated blood through the heart
aorta
pulmonary vein
which vessels carry deoxygenated blood through the heart
vena cava
pulmonary artery
where does blood flowing through the aorta go
pushes oxygenated blood around the body
where does blood from the vena cava go
deoxygenated blood back from the body tissue
where does the pulmonary vein go
brings oxygenated blood back from the lungs
where does the pulmonary artery go
carries deoxygenated blood to the lungs
