10 Variety of life

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  • Created by: Naana
  • Created on: 27-03-15 14:20
What is haemoglobin? What is the structure?
A globular protein in blood that readily combines with oxygen to transport it around the body. Primary structure-made of 4 polypeptide chains. Secondary structure-each polypeptide chain coiled into helix. Tertiary structure-each polypeptide chain fol
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What is the role of haemoglobin, and what does it need to do in order to be efficient?
To transport oxygen around the body. To be efficient at transporting oxygen haemoglobin must readily associate with oxygen at the surface where gas exchange takes place, and readily disassociate from oxygen at respiring issues
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How do haemoglobins from different organisms differ and why?
An organism living in an environment where there is little oxygen and has a low metabolic rate have haemoglobins with a high affinity for oxygen-they take up oxygen more easily but release it less readily. Whereas an organism living in an environment
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What happens to the affinity of haemoglobin when there is a high concentration of carbon dioxide?
The dissolved co2 is acidic and so the low pH causes the shape of the haemoglobin molecules to change. New shape binds more loosely to oxygen so the haemoglobin has a low affinity for oxygen. Oxygen is released more readily
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Why do different haemoglobins have different affinities for oxygen?
Because different haemoglobin molecules have slightly different sequences of amino acids and therefore slightly different shapes
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What is associating and dissociating of oxygen?
Associating- process where haemoglobin combines with oxygen (takes place in the lungs). Dissociating-process where haemoglobin releases its oxygen (takes place in the tissues)
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What happens when haemoglobin is exposed to different partial pressures of oxygen?
Haemoglobin doesn’t absorb oxygen evenly. At low concentrations of oxygen, the 4 polypeptides of the haemoglobin molecule are closely united and so it is difficult to absorb the first oxygen molecule. However once loaded, this oxygen molecule causes
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How does haemoglobin saturation depend on the partial pressure of oxygen?
Haemoglobin associates with oxygen to form oxyhaemoglobin when there is a high partial pressure (in the lungs). However oxyhaemoglobin dissociates with oxygen to form haemoglobin when there is a low partial pressure (in the respiring tissues- when ce
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What two things must you remember when looking at an oxygen dissociation curve?
1) The further to the left the curve, the greater the affinity of haemoglobin for oxygen-takes up oxygen more readily but releases it less easily. 2) The further to the right the curve, the lower the affinity of haemoglobin for oxygen- takes up oxyge
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What is starch? What is the structure of starch?
Starch is the main energy storage material in plants. Starch is a mixture of two polysaccharides of alpha glucose-amylose and amylopectin. Amylose is long, unbranched and coiled, whereas amylopectin is long and branched- which allows enzymes to break
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Why is starch good at storing energy?
It is insoluble- so does not draw water into cells by osmosis, it is compact- so a lot of energy can be stored in a small space, when hydrolysed it forms alpha glucose- glucose can be transported easily to cells and can be readily used in respiration
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What is cellulose? What is the structure of cellulose?
Cellulose is the major component of cell walls in plants, provides rigidity and prevents the cell from bursting. Cellulose is a polysaccharide made up of long unbranched chains of beta glucose. To form cellulose each beta glucose monosaccharide must
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What is glycogen? What is the structure of glycogen?
Glycogen is the main energy storage material in animals. Glycogen has shorter chains than starch and is highly branched. Because it is made of short chains it is very easily hydrolysed to give alpha glucose.
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Card 2

Front

What is the role of haemoglobin, and what does it need to do in order to be efficient?

Back

To transport oxygen around the body. To be efficient at transporting oxygen haemoglobin must readily associate with oxygen at the surface where gas exchange takes place, and readily disassociate from oxygen at respiring issues

Card 3

Front

How do haemoglobins from different organisms differ and why?

Back

Preview of the front of card 3

Card 4

Front

What happens to the affinity of haemoglobin when there is a high concentration of carbon dioxide?

Back

Preview of the front of card 4

Card 5

Front

Why do different haemoglobins have different affinities for oxygen?

Back

Preview of the front of card 5
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