Mass transport 4.0 / 5 based on 2 ratings ? BiologyMass transportASAQA Created by: LaellexCreated on: 26-05-16 09:34 What is the structure of haemoglobin? Quartnernary 1 of 25 How many oxygen atoms does it carry? 8- each ion combines with 02 2 of 25 What are the polypeptides associated with? A haeme group containing a ferrous iron (FeII) 3 of 25 What is high affinity? A haemoglobin that readily binds to oxygen and less readily releases it 4 of 25 What is low affinity? A haemoglobin that less readily binds with oxygen and releases it easily 5 of 25 When do haemoglobin associate with oxygen? At gas exchange surfaces 6 of 25 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 7 of 25 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. 8 of 25 Where is the dissociating curve for organisms with high affinity hameoglobin? To the left 9 of 25 What is to the right of the curve? Organisms with low affinity hameoglobin 10 of 25 Why is it difficult for the first oxygen molecule to bind? Because of the quarternary shape 11 of 25 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 12 of 25 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 13 of 25 What is the partial pressure of oxygen? 21 kPa 14 of 25 As the patrician pressure of carbon dioxide increases what happens to the graph? The curve shifts the the right, and haemoglobin so affinity reduces 15 of 25 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 16 of 25 What kind of affinity does an active organism need? Low- for respiration 17 of 25 What kind of affinity does a large organism need? High 18 of 25 Does a mouse need high or low affinity, why? Low, it loses heat more easily so needs increased metabolic activity to maintain heat 19 of 25 Mammals have what ratio of sa to. V? A small surface area to volume ratio 20 of 25 Why do mammals have a transport system? To take materials from cells to exchange systems 21 of 25 Names some features of a transport system? Suitable medium (water based), mass transport, closed system of tubular vessels, moving transport medium 22 of 25 Why should the medium be water based e.g. Blood? As liquids carry materials easily and substances can be dissolved 23 of 25 Why is mass transport needed? To transport the medium in bulk over large distances (faster than diffusion) 24 of 25 Why is a closed system of tubular vessels needed? It contains the medium forming branched networks that distribute to all parts of the organism 25 of 25
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