mass transport systems in organisms Booklet Flashcards
how can small organisms exhange materials with their environment
diffusion
why can small organisms exchange through diffusion?
large surface area to volume ratio
as organisms get larger they need specialised organs which maximise the exchange of materials by providing
a large surface area, short diffusion path and maintain concentration gradient
how do mammalian lungs maintain concentration gradient
blood circulation and ventilation of the lungs
how do fish gills maintain a concentration gradient
ventilation and countercurrent flow
how do plant leafs maintain a concentration gradient
Co 2 used by the cell in photosynthesis
how does the insect tracheal system maiantain a concentration gradient
oxygen used by respiring cells during respiration
mammals are endothermic what is meant by endothermic
mamels generate heat internally using respiration
what kind of circulatory system does a mammalian have?
double circulatory system
what is the double circulatory system composed of?
the pulmonary circuit and the systemic circuit
where is haemoglobin found?
in red blood cells
what are the adaption s of the protein to carrying oxygen?
contains four iron ions which bind to oxygen
definition of haemoglobin?
its a globular protein with a quaternary structure containing 4 polypeptide chains and 4 ham groups
what is the role of haemoglobin
to transport oxygen in the blood to respiring cells
what is meant by the term partial pressure?
the higher the concentration of a gas in a solution the higher the partial pressure
what is meant by affinity?
if something has a high affinity for oxygen, it readily binds to oxygen/ the degree to which a substrate tends to bind to another
what happens to haemoglobin in areas of high partial pressure of oxygen (eg lungs)
haemoglobin affinity for oxygen increases. Haemoglobin binds to oxygen and forms oxyhemoglobin. This is called loading
what happens to haemoglobin in areas of low partial pressure of oxygen (muscles)
haemoglobin affinity for oxygen decreases. Haemoglobin dissociates with oxygen. This is unloading
what is the oxygen dissociation curve showing?
co-operative bindin
explain how the co-operative nature of oxygen binding to haemoglobin causes the shape of the oxygen dissociation curve:
1)due to co-operative binding of first oxygen is difficult due to unexposed harm groups (so relatively large increase in partial pressure of oxygen is needed to bind to bind the first oxygen)
2)when the first oxygen is bound, the tierchary structure changes, exposing the harm binding sites which means subsequent oxygen molecules can bind more easily (so very small increases in partial pressure greatly increase the saturation of haemoglobin with oxygen)
3)when the third binds this further alter the tier chary structure and makes it more difficult o bind the last oxygen (so a very high partial pressure of oxygen is required so haemoglobin can find to the last fourth oxygen molecule)
when drawing the Bohr shift on to the graph you must
draw it shifting to the right and it must start and finish as the same as the other curve
describe what happens during the Bohr shift
1) as partial pressure C02 increases, haemoglobin affinity for oxygen decreases
2)this causes a shift to the right
3)this shows that there is more dissociation of oxygen from haemoglobin at a given partial pressure
4)the reason why carbon dioxide reduces haemoglobins affinity for oxygen is because it makes the blood acidic which alters the tier chary structure of haemoglobin
foetal haemoglobin is shifted to the left of adult haemoglobin. Explain the advantage to the foetus
1)foetal haemoglobin has a higher affinity for oxygen
2)this causes a shift to the left
3)this shows that there is less dissociation of oxygen from haemoglobin at a given partial pressure
4)this is an advantage as it means the foetus retains 02 at the placenta hone the mothers haemoglobin dissociates from it.
how have many animals adapted to their environment
by processing different types of haemoglobin with different oxygen transport properties
organisms with very high metabolic rate or who are very active
have haemoglobin with a lower affinity for oxygen (right shift) so ore oxygen dissociates at their respiring tissues
organisms that live in low oxygen environments, such as high altitude, deep sea down holes etc
have haemoglobin with high affinity for oxygen at low partial pressure (left shift) so they can load more oxygen at there gas exchange surface
describe the relationship between the size of the mammals and their oxygen dissociation curve
the larger mammals with have a higher affinity for oxygen so will have there dissociation curve further to the left
what is the role of the right hand side of the heart?
to receive deoxygenated blood and carry it to the lungs to be oxygenated
what is the role of the left hand side?
to receive oxygenated blood and carry it to the rest of the body respiring cells
what is meant by the term myogenic?
the stimulus for concentration orginates in the muscle itself and does not require nervous stimulation
what are the two upper chambers?
left and right atrium and they receive blood
what are the two lower chambers?
left and right ventricles. they send blood to the rest of the body and lungs
what is the role of the atrioventricular valves?
prevents the back flow and blood from
canary arteries
provides the cardiac muscle cells with glucose and oxygen to allow respiration to occur