transport of oxygen

Question 1

describe the structure of haemoglobin

Answer 1

primary- sequence of amino acids in a polypeptide chain by peptide bonds.
secondary- H bonds form and 2 polypeptide chains fold into beta pleated sheets and the other 2 coil into alpha helix
tertiary- ionic, disulphide bridges and hydrogen bonds form to form a specific 3d structure
quaternary- 4 polypeptide chains bond together in a spherical shape and form 4 haem groups

Question 2

define associate

Answer 2

oxygen binding to the haem group

Question 3

define dissociate

Answer 3

oxygen unbinding from the haem group

Question 4

define affinity for oxygen

Answer 4

how readily haemoglobin will bind to oxygen

Question 5

state in the body where you will find a high affinity for oxygen

Answer 5

in the lungs/alveoli

Question 6

state in the body where you will find a low affinity for oxygen

Answer 6

in respiring tissues

Question 7

what is partial pressure?

Answer 7

the concentration of a gas

Question 8

what is the unit of partial pressure?

Answer 8

kPa

Question 9

where in the body is there a high partial pressure ?

Answer 9

lungs

Question 10

where in the body is there a low partial pressure?

Answer 10

respiring tissues

Question 11

what shape is the oxygen dissociation curve?

Answer 11

s shaped

Question 12

what is the saturation of haemoglobin with oxygen at high partial pressures?

Answer 12

highly saturated

Question 13

what is the saturation of haemoglobin with oxygen at low partial pressures?

Answer 13

low saturation

Question 14

describe and explain the bohr effect

Answer 14

haemoglobin has a reduced affinity for oxygen in the presence of carbon dioxide. it loads oxygen less easily and unloads it more easily. dissolved carbon dioxide is acidic which causes the haemoglobin to change shape. at gas exchange surfaces, there is little CO2, affinity for oxygen is high, oxygen loads readily. at respiring tissues, CO2 concentration is high, affinity for oxygen is low, oxygen unloads easily

Question 15

why does the start of the oxygen dissociation curve have a shallow gradient?

Answer 15

it is hard for the first oxygen to bind to the haem group as its in the middle of the haemoglobin molecule

Question 16

why does the gradient of the oxygen dissociation curve get more steep?

Answer 16

the second and third oxygen molecules can bind more easily as the first has caused a conformational change in the haemoglobin molecule

Question 17

why does the oxygen dissociation curve level off?

Answer 17

the fourth oxygen cannot bind as easily as it is hard to reach the fourth oxygen binding site

Question 18

How does haemoglobin differ in different species?

Answer 18

Slightly different amino acid sequence so the tertiary and quaternary structure is different so has different oxygen binding properties