Transportation of Oxygen
- Created by: Emily Cartwright
- Created on: 30-05-14 10:24
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- Transportation of Oxygen
- Red blood cells
- Transport oxygen around the body
- Have many adaptations to increase the efficiency of oxygen transportation;
- This includes large surface area to volume ratio because;
- They are very small
- They don't have a nucleus which gives them a biconcave shape and increases the amount of space available for oxygen in the cytoplasm
- This includes large surface area to volume ratio because;
- Contain haemoglobin
- Haemoglobin
- Globular protein
- Quarternary structure - 4 polypeptide chains, each has a tertiary structure
- Specific 3D shape
- Each polypeptide chain contains a prosthetic group, a non protein part called a haem group
- Haem group contains iron ions (Fe2+). This forms loose association with oxygen
- The 3D shape of the haemoglobin provides a specific shaped bonding site for the oxygen
- As there are 4 haem groups, each molecule of haemoglobin can transport 4 moleucles of of oxygen
- When oxygen combines with haemoglobin, it is called oxyhaemoglobin
- The reaction is reversible, and when the oxygne leaves the haemoglobin it is said to dissociate
- When oxygen combines with haemoglobin, it is called oxyhaemoglobin
- As there are 4 haem groups, each molecule of haemoglobin can transport 4 moleucles of of oxygen
- The 3D shape of the haemoglobin provides a specific shaped bonding site for the oxygen
- Haem group contains iron ions (Fe2+). This forms loose association with oxygen
- Red blood cells can be thought of as an oxygen taxi
- They pick up oxygen in the lungs where the partial pressure is high, and drop off/unload in the tissues, where the partial is low and where the oxygen is needed for respiration
- They can only pick up and drop off at one site
- As they are only loosely associated with the oxygen, they can pick up and drop off easily and therefore association is reversible
- They can only pick up and drop off at one site
- They pick up oxygen in the lungs where the partial pressure is high, and drop off/unload in the tissues, where the partial is low and where the oxygen is needed for respiration
- The oxygen dissociation curve
- This shows the relationship between the partial pressure of the oxygen and the percentage saturation of the haemoglobin with oxygen
- The graph forms a sigmoid shaped curve. This is because the 4 oxygen molecules do not attach to the haem groups at the same time
- It is difficult for the first o2 molecules to bind to the haem group, but each time an O2 attaches,it makes it easier for the next O2 to bind to a haem group
- The graph forms a sigmoid shaped curve. This is because the 4 oxygen molecules do not attach to the haem groups at the same time
- The shape of the curve is significant
- The s shape indicates that haemoglobin is efficient at loading oxygen and can become fully saturated at a lower pO2 than if the relationship is linear
- Hb has a higher affinity for O2 at a relatively high partial pressure of O2 and will therefore load O2 to form oxyhaemoglobin
- This occurs in the capillaries of the tissues
- The steep part of the curve shows that for a relatively small decrease in pO2, there will be a large decrease in the % saturation of Hb with O2. This means more O2 will be unloaded to the tissues to carry out aerobic respiration
- This occurs in the capillaries of the tissues
- Hb has a higher affinity for O2 at a relatively high partial pressure of O2 and will therefore load O2 to form oxyhaemoglobin
- The s shape indicates that haemoglobin is efficient at loading oxygen and can become fully saturated at a lower pO2 than if the relationship is linear
- Dissociation curve shifts to the left
- These show a higher affinity for O2 and that at any given pO2, the % saturation of haemoglobin is higher than for normal adult haemoglobin
- Advantage is that more O2 can be loaded at a lower pO2
- Foetal haemoglobin
- Foetal haemoglobin has a higher affinity for O2 than normal Hb
- Therefore, at any given pO2, the % saturation of foetal Hb is higher than for normal adult Hb
- The significance of this is that the maternal Hb will unload approximately 70% of it's O2 to the tissues in the placenta. The foetal haemoglobin will then load O2 from the placenta to become approximately 80% saturated
- Therefore, at any given pO2, the % saturation of foetal Hb is higher than for normal adult Hb
- Foetal haemoglobin has a higher affinity for O2 than normal Hb
- Myoglobin
- Respiratory pigment found in muscle fibres - it has a very high affinity for O2
- This means that at any pO2, the % saturation of myoglobin is higher than normal Hb
- The significance of this is that;
- Myoglobin will retain it's O2 until very low pO2 levels occur for example, during intense exercise
- In this way, it delays the onset of anaerobic respiration
- Myoglobin will retain it's O2 until very low pO2 levels occur for example, during intense exercise
- The significance of this is that;
- This means that at any pO2, the % saturation of myoglobin is higher than normal Hb
- Respiratory pigment found in muscle fibres - it has a very high affinity for O2
- Foetal haemoglobin
- Advantage is that more O2 can be loaded at a lower pO2
- These show a higher affinity for O2 and that at any given pO2, the % saturation of haemoglobin is higher than for normal adult haemoglobin
- This shows the relationship between the partial pressure of the oxygen and the percentage saturation of the haemoglobin with oxygen
- Other respiratory pigments
- Some animals live in habitats with low O2 levels
- The lug worm lives in sand on the sea shore. It pumps sea water through it's burrow, giving access to the limited amount of dissolved oxygen present
- It's Hb has a high affinity for O2
- The advantage of this is that it can pick up more O2 and become fully saturated at lower pO
- It's Hb has a high affinity for O2
- The lug worm lives in sand on the sea shore. It pumps sea water through it's burrow, giving access to the limited amount of dissolved oxygen present
- Llamas
- Live at high altitudes where O2 levels are low
- It's Hb has a high affinity for O2
- The advantage of this is that it can pick up more O2 and become fully saturated at a lower pO2
- At high altitudes, the number of red blood cells in the blood of mammals increases
- The advantage of this is that it can pick up more O2 and become fully saturated at a lower pO2
- It's Hb has a high affinity for O2
- Live at high altitudes where O2 levels are low
- Some animals live in habitats with low O2 levels
- Dissociation curve shifts to the right (Bohr effect)
- During exercise, muscles work harder, so they need more ATP . Therefor , the rate of respiration increases
- This also produces more CO2, which lowers the pH of the blood
- The causes the dissociation curve to shift to the right, known as the Bohr effect
- The Hb now has a lower affinity for O2
- At any given pO2, the % saturation of the Hb is lower than for normal adult Hb
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- At any given pO2, the % saturation of the Hb is lower than for normal adult Hb
- The Hb now has a lower affinity for O2
- The causes the dissociation curve to shift to the right, known as the Bohr effect
- This also produces more CO2, which lowers the pH of the blood
- During exercise, muscles work harder, so they need more ATP . Therefor , the rate of respiration increases
- Red blood cells
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