Haemoglobin & Oxygen Transport: OCR AS

  • Created by: Aleena
  • Created on: 18-11-18 13:34
Solubility of Oxygen in water?What does this mean?
quite low-means dissolved oxygen in blood plasma, would never be enough to supply the body's needs
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Haemogloblin?
Is a protein-made of 4 polypeptide chains: 2 alpha + 2 beta chains. Each chain has a iron-containing haem group.
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What does the Haem group allow Haemoglobin to do?
Haem group allows it to bind with oxygen-1 Oxygen molecule per haem group
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what are the 2 forms Haemoglobin exists in?
Oxyhaemoglobin & Deoxyhaemoglobin
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Affinity?
A natural attraction
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Partial Pressure?
pressure exerted by 1 component of a mix of gases. Units: mmHg or kPa
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The affinity of haemogloblin trend?
affinity of haemogloblin increases with partial pressure of oxygen
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Why is it easier to absorb another oxygen molecule if you have already absorbed one?
when a haem group absorbs 1 oxygen molecule-alters structure of haemogloblin molecule-this makes it easier to absorb the second,third, oxygen molecules.
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Partial pressure of oxygen in lungs and in respiring tissues
lungs-high & tissues-low
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Explain how the changing affinity for oxygen, makes Haemogloblin well adapted for body's needs?
Haemogloblin needs a high affinity to absorb O2 but this makes it unlikely to dissociate with O2-but as affinity varies with kPa the problem is solved.High kPa-lungs so associate with O2 tissues-low kPa so dissociate with O2
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Bohr Effect?
Increasing levels of CO2 lower the affinity of haemolgloblin for oxygen-so even more oxygen is released.
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What causes the Bohr Effect?
CO2 Levels & decreasing levels of pH CO2 creates
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In mammals how does the fetus get its oxygen?
from mum's blood via the placenta
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Partial pressure of O2 in placenta?
kPa of O2 is lower than the kPa in adult lung-could cause fetus problems in absorbing sufficient O2. So fetus haemogloblin has 2 gamma polypeptide chains instead of beta-this haemolglobin has a higher affinity for O2 than mum so can absorb O2 from it
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when is the fetal haemoglobin replaced with the adult one?
first few months after birth
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When does the oxygen dissociation curve shift to the left?
Underground,high altitude and fetus- max saturation of O2 reached earlier-means Haemoglobin associates with O2 more readily
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Card 2

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Haemogloblin?

Back

Is a protein-made of 4 polypeptide chains: 2 alpha + 2 beta chains. Each chain has a iron-containing haem group.

Card 3

Front

What does the Haem group allow Haemoglobin to do?

Back

Preview of the front of card 3

Card 4

Front

what are the 2 forms Haemoglobin exists in?

Back

Preview of the front of card 4

Card 5

Front

Affinity?

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