unit 3, haemoglobin and dissociation curve

Question 1

what is the structure of haemoglobin?

Answer 1

-quaternary structure
-4 polypeptide chains
-each chain has an iron ion, which is where oxygen binds
-globular
-shperical

Question 2

What is the function of haemoglobin?

Answer 2

allows red blood cells to transport oxygen from the lungs to all other parts of the body.

Question 3

what is affintiy of haemoglobin with oxygen?

Answer 3

the ability of haemoglobin to attract or bind to oxygen

Question 4

what is saturation of haemoglobin with oxygen?

Answer 4

haemoglobin holding the maximum amount of oxygen it can

Question 5

what is loading/associating?

Answer 5

haemglobin taking on oxygen

Question 6

what is unloading/dissociating?

Answer 6

heamoglobin releasing oxygen

Question 7

what happens on the oxyhaemoglobin dissociation curve at lower partial pressure?

Answer 7

There is lower affinity, so there is higher unloading of oxygen. This occurs at muscle tissues when they are respiring.

Question 8

what happens on the oxyhaemoglobin dissociation curve at higher partial pressure?

Answer 8

There is higher affintiy, and higher saturation, lots of loading of oxygen. This happens at the Alveoli.

Question 9

what is co-operative binding?

Answer 9

the 1st binding slightly changes the 3D shape, the quaternary structure, allowing further oxygen to bind/load easier.

Question 10

what is the Bohr effect?

Answer 10

-When there is high concentration of Carbon Dioxide it causes there to be a lower affinity of heamoglobin for oxygen, becasue the acidic carbon dioxide changes the shape of haemoglobin slightly to prevent it from loading as much oxygen. This is an advantage for respiring.

Question 11

what happens to affinity when there is low amount of carbon dioxide?

Answer 11

-affinity for oxygen increases and a higher partial pressure is needed to bind effectively.

Question 12

which way does the curve shift if there is high amounts of carbon dioxide?

Answer 12

to the right
-remember,right release

Question 13

will the gradient be high or low when there is more carbon dioxide?

Answer 13

low, it is not as steep

Question 14

does a fetus have a high of low affinity for oxygen? example

Answer 14

high affinity
-because fetus are unable to inhale or exhale they have a high affinity to load as much oxygen as possible

Question 15

does a Llama living at high altitudes have a high or low affinity for oxygen? example

Answer 15

high affinity
-due to lack of oxygen at high altitudes, needs to load as much as possible

Question 16

does a Dove have a high or low affinty for oxygen? example

Answer 16

low affinity
-due to Doves constantly flying they need to have constant respiration, therefore the affinity is low

Question 17

does a Earthworm have a high or low affinity for oxygen? example

Answer 17

high affinity
- due to lack of oxygen underground they need to have high affinity to load as much oxygen as possible

Question 18

on the oxygen dissociation curve what happens at each stage 1-4?

Answer 18

1) the partial pressure is low, the gradient is shallow, therefore the oxygen has been unloaded so the shape is tight. the tight shape makes it harder for other oxygen to bind, low affinity. e.g.) at muscle
2) the binding of the second oxygen changes the quaternary shape of the haemoglobin, making it easier for the other oxygen to bind. the affinity is increasing and there is a positive small increase in the gradient. there is co-operative binding. High affinity.
3)binding of the third oxygen causes the quaternary structure to loosen , the affinity has further increased. less increase of partial pressure to bind oxygen.
4)binding becomes harder again, because its hard to locate the last lost unbound site. the affinity is high, but there is a shallow gradient.

Question 19

How does an increase in carbon dioxide affect haemoglobin?

Answer 19

-means there is more carbonic acid, which changes the quaternary shape of haemoglobin. Because there is protons that cause the release of oxygen

Question 20

when carbon dioxide is high, is the pH of blood high or low?

Answer 20

The pH of blood is lowered from high PCo2, due to the carbonic acid that is formed. acid is low on the pH scale.

Question 21

at what stage does deoxyhaemoglobin become oxyhaemoglobin?

Answer 21

stage 4, when all oxygen has binded to the haemoglobin.

Question 22

where is carbon dioxide carried?

Answer 22

dissolved, in the blood plasma.