Please enable JavaScript.
Coggle requires JavaScript to display documents.
strand 3 (part 2) - Coggle Diagram
strand 3 (part 2)
haemoglobin
primary protein ~ the specific base sequence of amino acids in a polypeptide chain bonded by covalent peptide bonds
secondary protein ~ alpha helix/beta pleated sheets with hydrogen bonds between the amino group and the carboxyl group
tertiary protein ~ complex 3D structure with hydrogen, ionic and disulphide bonds between the R group, folds depend on the position of the R group
quaternary protein ~ multiple polypeptide chains working together as a functional macromolecule such as haemoglobin, each peptide chain is known as a subunit
globular proteins ~ these are round, compact and easily soluble so they can be transported in fluids, examples are haemoglobin and enzymes
Haemoglobin is a globular protein. Its structure is curled up so that hydrophilic side chains face outwards and hydrophobic side chains face inwards. This makes haemoglobin soluble and therefore good for transport in the blood.
Oxygen transport
Haemoglobin is a globular protein made up of 4 peptide chains, each chain contains one haem (iron) group containing a Fe2+ ion. Each haem group can combine with one oxygen molecule (O2). Oxyhaemoglobin.
Hb + 4O2 —> <— Hb(O2)4 (reversible reaction)
-
-
Blood saturated to around 96% of oxygen is where haemoglobin becomes oxyhaemoglobin. Oxygen will move from a high to a low partial pressure of oxygen. At low partial pressures there isn't a great deal of change in the saturation of Hb. A small change in the pO2 can result in a large change in the percentage saturation of the blood. At higher partial pressures there isn't a great deal of change in the saturation of Hb.
The first molecule of O2 combines with an Hb and slightly distorts it. The joining of the first is quite slow as it is quite difficult for oxygen to bind to the closely packed chains. After the quaternary structure of the Hb has changed shape a little, it becomes easier and easier for the second and third O2 to join (positive cooperativity). It flattens off at the top. Theoretically it should be easy for the fourth molecule to bind; however, the probability of the final oxygen binding to the haemoglobin decreases.
circulatory systems
mass transport system
Multicellular animals have a low surface area to volume ratio and a high metabolic rate so they require a specialised transport systems to carry raw materials from specialised exchange organs to their body cells.
-
cardiac cycle
definitions
-
-
stages
diastole
-
-
Blood under high pressure in the arteries is drawn back towards the ventricles, closing the semi-lunar valves, preventing back flow.
The coronary arteries fill during diastole.
Blood under low pressure flows into the atria from the pulmonary veins and vena cava.
As the atria fill, the pressure of blood against the atrioventricular (AV) valves pushes them open and blood leaks into ventricles. (the pressure in the artria exceeds the pressure in the ventricles)
atrial systole
The atria walls contract, forcing the remaining blood into the ventricles.
Pressure in atria is higher than ventricles
ventricular systole
The ventricles contract from the bottom of the heart (apex) upwards, increasing the pressure in the ventricles.
Blood is pushed through the arteries as the pressure in the ventricles exceeds the pressure in the arteries, opening the semi-lunar valves.
The pressure of the blood against the AV valves closes them, preventing back flow.