transport of oxygen Flashcards

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1
Q

describe the structure of haemoglobin

A

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

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2
Q

define associate

A

oxygen binding to the haem group

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3
Q

define dissociate

A

oxygen unbinding from the haem group

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4
Q

define affinity for oxygen

A

how readily haemoglobin will bind to oxygen

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5
Q

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

A

in the lungs/alveoli

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6
Q

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

A

in respiring tissues

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7
Q

what is partial pressure?

A

the concentration of a gas

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8
Q

what is the unit of partial pressure?

A

kPa

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9
Q

where in the body is there a high partial pressure ?

A

lungs

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10
Q

where in the body is there a low partial pressure?

A

respiring tissues

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11
Q

what shape is the oxygen dissociation curve?

A

s shaped

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12
Q

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

A

highly saturated

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13
Q

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

A

low saturation

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14
Q

describe and explain the bohr effect

A

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

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15
Q

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

A

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

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16
Q

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

A

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

17
Q

why does the oxygen dissociation curve level off?

A

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

18
Q

How does haemoglobin differ in different species?

A

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