Mass transport

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  • Created by: Laelle
  • Created on: 26-05-16 09:34
What is the structure of haemoglobin?
Quartnernary
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How many oxygen atoms does it carry?
8- each ion combines with 02
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What are the polypeptides associated with?
A haeme group containing a ferrous iron (FeII)
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What is high affinity?
A haemoglobin that readily binds to oxygen and less readily releases it
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What is low affinity?
A haemoglobin that less readily binds with oxygen and releases it easily
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When do haemoglobin associate with oxygen?
At gas exchange surfaces
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What happens to haemoglobin in the presence of carbon dioxide?
It changes shape, and binds more loosely to the oxygen. The oxygen is released from haemoglobin
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Why do different organisms have different types of haemoglobin?
Because they have different amino acid sequences, so have different quarternary structures. Hence different oxygen brining properties.
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Where is the dissociating curve for organisms with high affinity hameoglobin?
To the left
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What is to the right of the curve?
Organisms with low affinity hameoglobin
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Why is it difficult for the first oxygen molecule to bind?
Because of the quarternary shape
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What is it easier for the 2nd and 3rd molecule to bind?
Because of positive cooperativity- the first molecule binding changes the shape of the molecule making it easier for other molecules to bind
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What does the graph flatten off (difficulty of 4th molecule binding)?
Because of probability- the majority of binding sites are occupied so there's less chance of finding an empty site
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What is the partial pressure of oxygen?
21 kPa
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As the patrician pressure of carbon dioxide increases what happens to the graph?
The curve shifts the the right, and haemoglobin so affinity reduces
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Why does affinity reduce in the presence of carbon dioxide?
Because it is acidic, and the low pH class the hameoglobin to change shape so it more easily unloads oxygen
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What kind of affinity does an active organism need?
Low- for respiration
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What kind of affinity does a large organism need?
High
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Does a mouse need high or low affinity, why?
Low, it loses heat more easily so needs increased metabolic activity to maintain heat
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Mammals have what ratio of sa to. V?
A small surface area to volume ratio
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Why do mammals have a transport system?
To take materials from cells to exchange systems
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Names some features of a transport system?
Suitable medium (water based), mass transport, closed system of tubular vessels, moving transport medium
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Why should the medium be water based e.g. Blood?
As liquids carry materials easily and substances can be dissolved
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Why is mass transport needed?
To transport the medium in bulk over large distances (faster than diffusion)
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Why is a closed system of tubular vessels needed?
It contains the medium forming branched networks that distribute to all parts of the organism
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Other cards in this set

Card 2

Front

How many oxygen atoms does it carry?

Back

8- each ion combines with 02

Card 3

Front

What are the polypeptides associated with?

Back

Preview of the front of card 3

Card 4

Front

What is high affinity?

Back

Preview of the front of card 4

Card 5

Front

What is low affinity?

Back

Preview of the front of card 5
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