Mass Transport Flashcards
What are the adaptations of a red blood cell
No nucleus so more room for haemoglobin
Bi concave shape
Pits the capillary perfectly so there is a short diffusion pathway
Protein structure of haemoglobin (primary - quaternary)
Primary - two alpha and two beta polypeptide chains
Secondary - each polypeptide chain folds into a helix
Tertiary - polypeptide chain is folded into a precise shape
Quaternary- all 4 polypeptides are linked to make a spherical shape each associated with a haem group with iron
How many oxygen molecules can each human haemoglobin molecule Carry
4
How many oxygen atoms can two haemoglobin molecule carry and why
16 because there would be 8 oxygen molecules with two atoms each
Describe the role of oxygen affinity in haemoglobin
Affinity must be high where oxygen loads (lungs )
But it decreases at the respiring tissue so that oxygen can unload
What factors effect the type of haemoglobin present in an organism
Amino acid sequence
Shape of molecule
Why is only one of the 4 oxygen molecules released when the body is at rest
So that more oxygen can be delivered to tissue when they become more active
What is a erythrocyte
Red blood cell
What is partial pressure
In a mixture of gasses the pressure of one gas if it alone filled the container
What does cooperativity mean in terms of loading oxygen
When one oxygen binds the structure of the haemoglobin changes shape slightly making it easier for future oxygen molecules to bind
Explain the shape of the oxygen dissociation curve
At the beginning oxygen struggles to bind with the haemoglobin once one sxygen has bound to the haem group the gradient of the line increases because the quaternary structure of the haemoglobin moves slightly. This is cooperative and allows three other oxygens to load easily
Describe how partial pressure affects oxygen association
Haemoglobin slightly saturated with oxygen at higher partial pressure
Drop in partial pressure leads to rapid decrease in % saturation of haemoglobin
This favours loading oxygen in the lungs and unloading in the tissue
Describe the Bohr shift
In Actively respiring tissue carbon dioxide concentration increases which dissolves in the blood plasma. This forms carbonic acid so there is an increase in H+ ions causing a decrease in blood pH
More oxygen is more easily unloaded because of the lower affinity of oxygen due to the pH reduction. This means more oxygen is available for respiration at the same partial pressure
The Bohr effect is reversed in the alveoli because carbon dioxide conc is low , so loading of oxygen is easier because higher affinity of haemoglobin for oxygen bought about by pH increase
What is the oxygen dissociation curve for lug worms and llama ( and which way does it move)
Moves to the far left
They have a higher affinity for oxygen because they live in low partial pressure areas
What does the foetal oxgyen dissociation curve look like (and where does it move )
Moves slightly left
It has a higher affinity for oxygen because partial pressure at placenta can associate more oxygen from the mother
What does the oxygen dissociation curve look like for small mammals as birds (and where does it move)
Moves to the right
They are highly metabolically active so are adapted to release oxygen more readily
Lower affinity for oxygen
How do simple animals transport things and why
Diffusion because of their small surface area to volume ratio
How do larger animals transport stuff and why
Transport systems
Because they have a smaller surface area to volume ratio and diffusion would be to slow
What determines if a transport system needs a pump
The surface area to volume ratio
How active it is
Distance to the centre
Why is it important Mammels have a double closed circulatory system
Because when blood passes the lungs its pressure decreases and if it then went straight to the body it wouldn’t have enough pressure to get all the way round so it must return to the heart to increase the pressure
Why does the aorta have the highest pressure
It is coming from the left ventricle which is muscular as it contracts
Why does the vena cava have the lowest pressure
It is returning to the right atrium and has travelled the furthest around the body
How to describe data
Double data quote ( x and y ) and units
Then quantify with trends
Describe how blood flows through the heart
The right atrium receives deoxygenated blood in the vena cava from the body and the right ventricle pumps through the pulmonary artery to the lungs
The left atrium receives oxygenated blood through the pulmonary vein and and the left ventricle pumps it to the body through the aorta
What are the functions of the valves in the heart
Atrioventricular valves are attached to the ventricles by pupillary muscles which prevent the valves from inverting under high pressure
Describe diastole
Heart muscle is relaxed
Atria and ventricles fill with blood
Semi lunar valves close
Pressure in atrium exceeds ventricle so atrioventricular valves open