Transport of Oxygen by Haemoglobin

Description

AQA
Joanne North
Flashcards by Joanne North, updated more than 1 year ago
Joanne North
Created by Joanne North about 7 years ago
6
0

Resource summary

Question Answer
What is haemoglobin? Protein molecules with a quaternary structure that has evolved to make it efficient at loading oxygen under one set of conditions but unloading it under a different set of conditions.
What are the main structures that make up a haemoglobin molecule? 1. Primary Structure 2. Secondary Structure 3. Tertiary Structure 4. Quaternary Structure
What is the primary structure of haemoglobin? The sequence of amino acids in the four polypeptide chains.
What is the secondary structure of haemoglobin? Each polypeptide chain is coiled into a helix.
What is the tertiary structure of haemoglobin? Each polypeptide chain is folded into a precise shape - which is an important factor in its ability to carry oxygen.
What is the quaternary structure of haemoglobin? All four polypeptide chains are linked together to form a spherical molecule. Each polypeptide chain id associated with a haem group.
What does a haem group contain? Fe2+ ion (iron)
How many oxygen molecule can a iron ion combine with? 1 O2 molecule
How many molecule of oxygen can be carried by a haemoglobin molecule? 4
Define loading (associating) of oxygen The process by which haemoglobin binds with oxygen
Where does loading or associating of oxygen take place? The lungs.
Define unloading (dissociating) of oxygen The process by which haemoglobin releases its oxygen.
Where does unloading or dissociating take place? In the tissues.
What do haemoglobins with a high affinity for oxygen do? Take up oxygen more easily, but release it less easily.
What do haemoglobins with a low affinity for oxygen do? Take up oxygen less easily, but release it more easily.
What is the main role of haemoglobin? To transport oxygen
For haemoglobin to be efficient at transporting oxygen, haemoglobin must? a. Readily associate with oxygen at the gas exchange surface. b. Readily dissociate from oxygen at those tissues requiring it.
Why do different haemoglobins have different affinities for oxygen? Each haemoglobin molecule of a different species has a different sequence of amino acids which produces a slightly different tertiary and quaternary structure. This change in structure means it will have different binding sites.
What does a oxygen dissociation curve show? The relationship between the saturation of haemoglobin with oxygen and the partial pressure of oxygen.
Explain this oxygen dissociation curve 1. Initially the curve is shallow as the shape of the haemoglobin molecule makes it hard for the first molecule of oxygen to bind. 2. The binding of the first oxygen molecule changes the quaternary shape of haemoglobin making it easier for other oxygen molecules to attach. 3. It therefore takes a smaller increase in partial pressure for the second and third molecule to attach so the curve steepens. 4. The binding of the fourth haemoglobin molecule is much harder due to probability as the majority of the sites are taken so the curve flattens off.
If a curve on an oxygen dissociation graph is further to the left then..? There is a greater affinity of haemoglobin for oxygen (loads easily).
If a curve on an oxygen dissociation graph is further to the right then..? There is a lower affinity of haemoglobin for oxygen (readily unloads).
What is the Bohr effect? The greater the concentration of carbon dioxide, the more readily the haemoglobin will release its oxygen.
In the lungs is the oxygen dissociation curve further to the left or right? Left as there is a reduced concentration in carbon dioxide.
In the respiring tissues is the oxygen dissociation curve further to the left or right? Right as there is an increased amount of carbon dioxide.
What are the stages of loading, transporting and unloading of oxygen? 1. At a gas exchange surface carbon dioxide is constantly being removed. 2. The pH is slightly raised due to the low concentration of carbon dioxide. 3. The higher the pH changes the shape of haemoglobin into one that enables it to load oxygen easily. 4. This shape also increases the affinity of haemoglobin for oxygen, so it is not released during transport. 5. In the tissues, carbon dioxide is produced by respiring tissues which is acidic so the pH of the blood is lowered. 6. The lower the pH changes the shape of haemoglobin into one of lower affinity for oxygen so releases its oxygen in the respiring tissues.
Describe unloading oxygen at the tissues. 1. The higher the rate of respiration. 2. The more carbon dioxide tissues produce. 3. The lower the pH. 4. The greater the affinity for haemoglobin to change its shape. 5. The more readily oxygen is unloaded. 6. The more oxygen is available for respiration.
What is an example of an animal that lives in an environment with a low partial pressure for oxygen? A lugworm. Has to extract as much oxygen as possible to survive until the tide comes back in.
Show full summary Hide full summary

Similar

Biology AQA 3.2.5 Mitosis
evie.daines
AQA Biology 8.1 structure of DNA
Charlotte Hewson
Biology AQA 3.1.5 The Biological basis of Heart Disease
evie.daines
Biological Definitions
Yamminnnn
GCSE Biology AQA
isabellabeaumont
A level Computing Quiz
Zacchaeus Snape
Biology AQA 3.1.3 Cells
evie.daines
GCSE AQA Biology - Unit 2
James Jolliffe
GCSE AQA Biology 1 Quiz
Lilac Potato
B3 Quiz
Tess Brockway
Love through the ages
acasilva001