Mrs H bio 6 haemoglobin

Question 1

How many polypeptide chains is haemoglobin made up of?

Answer 1

4

Question 2

How many subunits does a haemoglobin contain?

Answer 2

4

Question 3

What type of bond are the globin subunits held by?

Answer 3

Disulphide bridges

Question 4

What does the haem group contain?

Answer 4

Iron

Question 5

Why does the haem group contain iron?

Answer 5

Iron is able to reversibly my combine with an oxygen molecule forming oxyhaemoglobin

Question 6

How many oxygen molecules can each haemoglobin carry?

Answer 6

4

Question 7

What is the function of haemoglobin?

Answer 7

Responsible for binding oxygen in the lungs and transporting the oxygen to the tissue

Question 8

What is cooperative binding?

Answer 8

The binding of the first oxygen molecule results in a conformational change in the structure of the haemoglobin molecule, making it easier for each successive O2 molecule to bind

Question 9

Describe the process of haemoglobin

Answer 9

At the lungs the partial pressure of O2 is high and due to the Hb’s high affinity for O2 it loads the O2 to become saturated
And then when it reached the cells + tissues there is a lower partial pressure of O2 and the Hb has a lower affinity for O2 so they unload the O2 so the haemoglobin is less saturated

Question 10

Why does the Hb have a power affinity at the cells and tissues?

Answer 10

Because of the higher CO2 conc cause by respiration which decreases the Ph and causes the ionic bonds to break and the tertiary structure to change

Question 11

what is the purpose of iron in haemoglobin?

Answer 11

reversibly combine with an oxygen molecule forming oxyhaemoglobin

Question 12

why is the Oxygen disassociation curve S shaped?

Answer 12

due to shape of haemoglobin it is difficult for the 1st oxygen molecule to bind meaning the curve will initially be shallow then after the 1st molecule has binded, haemoglobin protein will change shape and create a new binding site making it easier and quicker for the remaining molecules to bind causing the graph to be steeper. As haemoglobin reaches saturation, taaes longer for the 4th molecule to bind due to shortage of remaining binding sites causing the curve to level off

Question 13

give the effect of increased respiration on oxygen disassociation

Answer 13

1.tissure cells respire quickly
2.respiration uses O2 surrounding tissue and porudces CO2
3.this reduces PO2 to a lower level than normal
4. haemoglobin will become more disassociated (less saturated) + more O2 will be released from haemoglobin to the tissue cells

Question 14

what is the effect of carbon dioxide concentration on oxygen disassociation?

Answer 14

in high concs of CO2, haemoglobins affinity for O2 is lowered so as CO2 levels increase, saturation of Hb decreases, as a result more O2 is released from Hb and is available to respiring cells

Question 15

what does a shift to the right mean for the oxygen disassociation?

Answer 15

more oxygen unloaded -> more O2 to respiring tissues

Question 16

why does Hb have a lower affinity at higher levels of C02?

Answer 16

when C02 dissolves in the blood it forms carbonic acid which lowers the pH. H ions from the acid bind to Hb causing the release of O2

Question 17

what are the 3 types of Hb?

Answer 17

1. Hb found in adult humans + other species that live on land and sea
   2.Hb found in species in environments where ppO2 is low
2. Hb found in species with a high metabloic rate

Question 18

how is the haemoglobin of a species found in environments where ppO2 is low adapted?

Answer 18

-disassociation curve shifted to the left
-their Hb has a higher affinity for O2
-becomes fully saturated at a lower ppO2 + rapidly unloads when Hb passes through tissues
(left shift leads to more unloading)

Question 19

how is the haemoglobin in species with a high metabolic rate adapted?

Answer 19

• Hb has a lower affinity for 02
  -disassociates from Hb more readily
  -02 is more readily available to respiring tissues
  (right shift due to more respiration)

Question 20

give an example of an organism with Hb adapted for low environmental ppO2

Answer 20

human foetus