7.1 haemoglobin Flashcards
what does the primary structure of haemoglobin look like?
sequence of amino acids
what does the secondary structure of haemoglobin look like?
polypeptide chain is coiled into a helix by hydrogen bonds
what does the tertiary structure of haemoglobin look like?
polypeptide chain is folded into a precise shape by ionic bonds, hydrogen bonds and disulphide bridges
what does the quaternary structure of haemoglobin look like?
4 polypeptides linked with each polypeptide associated with a haem group
what is meant by loading/ associated?
process by which the haemoglobin binds with oxygen
what is meant by unloading/ dissociating?
process by which haemoglobin releases its oxygen
what is the role of haemoglobin?
- readily associate with oxygen at the surface where gas exchange takes place
- readily dissociate from oxygen at those tissues requiring it
explain how DNA leads to different haemoglobin molecules having different affinities for oxygen
- different base sequence in DNA
- different amino acid sequence
- different tertiary and quaternary structure and shape
- different affinity for oxygen
when the body is at rest, only one of the four oxygen molecules carried by haemoglobin is normally released into the tissues. suggest why this could be an advantage when the organism becomes more active
if all oxygen molecules were released, there would be none in reserve to supply tissues when they were more active
carbon monoxide occurs in car exhaust fumes. it binds permanently to haemoglobin in preference to oxygen. suggest a reason why a person breathing in car- exhaust fumes might lose consciousness.
- carbon monoxide will gradually occupy all the sites on haemoglobin instead of oxygen
- no oxygen will be carried to tissues
- these will cease to respire and to function, making the person lose consciousness
