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hassanibnali
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Can anyone explain how copper sulphate denatures egg albumin?
i need to find the lowest concentration of copper sulphate solution that brings about full denaturation of egg albumen.
Thank you!
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copper is a heavy metal, and is highly elecropositive. Within proteins exist ionic bonds between the -COO groups on one amino, and the NH2 groups on others. When copper(II) ions are added, they are more electrostatically attractive, and therefore they bond in favour of the weaker exisiting ionic bonds. This causes the shape of the protein to be altered, and thus the protein is denatured.

Hope this is some help, Harry.
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hey cud u please tell me where u got this info from as id like to add to my references and i dont think a messageboard counts

thanks Ems
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what method can i use to measure the opaqueness of the egg albumen during the denaturation when different concentrations of copper sulphate are added? any replies then can you send to [email protected] thankyou very much, bec xx
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xxx
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hey does anyone know how 2 work out the concentration of the cuso4 pls let me know.i've dun a experiment 2 test the denaturasation of the egg and i used from 9 to 1 ml but is that right cos i haven't worked out y im using that concentration.
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In order to get the "opaqueness" measured, your school needs to have a "Colorimeter" - ask your biology teacher if they have one.

Also, to work out the CU concentration you gotta work in fractions (it's easiest).

1> 10 ml CU, 0ml Water (100%)
2> 10 ml CU, 10ml Water (50% - It's half and half)
3> 10 ml CU, 20ml water (33.3% - it's now in thirds (three 10ml portions))
4> 10 ml CU, 30ml water (half of 25% - it's now in quaters (4 10ml portions).

1. 0.1 concentration
2. 0.05 concentration
3. 0.0333333333 (etc etc) Concentration
4. 0.025 concentration
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RC.
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Originally posted by Unregistered
copper is a heavy metal, and is highly elecropositive. Within proteins exist ionic bonds between the -COO groups on one amino, and the NH2 groups on others. When copper(II) ions are added, they are more electrostatically attractive, and therefore they bond in favour of the weaker exisiting ionic bonds. This causes the shape of the protein to be altered, and thus the protein is denatured.

Hope this is some help, Harry.
I'd like to shoot this theory down. Yes, there are bonds between COO and NH2 groups, but those are the covalent peptide bonds that form the main chain links between amino acids..

THe R groups have the IONIC bonds, whcih are affected by both the sulphate and copper ions, as both are attracted to the charged R groups, neutralising the charge and breaking the bond. This is what causes the protein to denature, not the above. (no offence, I just don't want people to be confused).
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Originally posted by xxx
hey does anyone know how 2 work out the concentration of the cuso4 pls let me know.i've dun a experiment 2 test the denaturasation of the egg and i used from 9 to 1 ml but is that right cos i haven't worked out y im using that concentration.
The concentration can be worked out using a formula
new concentration = orginal concentration/ Dilution factor
The dilution factor is the total amount of liquid
(I think) but hope this helps
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Originally posted by Unregistered
In order to get the "opaqueness" measured, your school needs to have a "Colorimeter" - ask your biology teacher if they have one.

Also, to work out the CU concentration you gotta work in fractions (it's easiest).

1> 10 ml CU, 0ml Water (100%)
2> 10 ml CU, 10ml Water (50% - It's half and half)
3> 10 ml CU, 20ml water (33.3% - it's now in thirds (three 10ml portions))
4> 10 ml CU, 30ml water (half of 25% - it's now in quaters (4 10ml portions).

1. 0.1 concentration
2. 0.05 concentration
3. 0.0333333333 (etc etc) Concentration
4. 0.025 concentration
this is wrong because you have to keep your volumes the same so tryusing

10ml of cus04 and 0ml of water (100%conc) then
5ml of cuso4 and 5ml of water (50%conc)
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Unregistered
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try working in moles, it looks better. also a colorometer is accurate enough at this stage, just pretend your school has a brilliant one. i was hoping if anyone could supply a decent range, and table.

also dont forget to make sure u emphasise ur repeating the experiments, easy marks. to get the accuracy marks try using a burette to make sure you do have 10 ml of the stuff, not 9.9 or anything..
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Originally posted by RC.
I'd like to shoot this theory down. Yes, there are bonds between COO and NH2 groups, but those are the covalent peptide bonds that form the main chain links between amino acids..

THe R groups have the IONIC bonds, whcih are affected by both the sulphate and copper ions, as both are attracted to the charged R groups, neutralising the charge and breaking the bond. This is what causes the protein to denature, not the above. (no offence, I just don't want people to be confused).
so what is right then? and erm, does the fact that it is copper II make a difference to anything?

wish i had done chemistry too..........
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RC.
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No, the fact that it is copper has little to do with it. It's merely the fact that it has charge, which interferes with the Ionic bond between R groups.
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but it has posotive charge because it is a heavy metal, am i right?
errr........ what does it mean by a 'heavy' metal?
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#14
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Doesn't the SO4 2- compound ion form with any H+ ions to form sulphuric acid which can then denature the enzymes because of a low pH level or is this jus bull?
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RC.
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Originally posted by Unregistered
but it has posotive charge because it is a heavy metal, am i right?
errr........ what does it mean by a 'heavy' metal?
copper is a transition metal. The heavy metals are the lanthanoids, actinoids and the metals found in the lower right hand corner of the periodic table such as lead.

It is positively charged because it is a metal, but there are also positively charged covalent molecules of non metals.

As for SO4 2- Ion, It must donate H+ Ions to be acidic. Acidity is measured as concentration of H+ Ions.

H2SO4 disociates when added to solution, adding 2 H+ Ions to solution, increasing the acidity.

Note, only H+ Ions are acidic, not positive Ions in general.

So if the SO4 2- aborbed H+ Ions, it would not cause acidity but the reverse.

In conclusion, It's just the charged particles in general that cause the molecule to denature.
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Originally posted by Unregistered
copper is a heavy metal, and is highly elecropositive. Within proteins exist ionic bonds between the -COO groups on one amino, and the NH2 groups on others. When copper(II) ions are added, they are more electrostatically attractive, and therefore they bond in favour of the weaker exisiting ionic bonds. This causes the shape of the protein to be altered, and thus the protein is denatured.

Hope this is some help, Harry.
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#17
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#17
Originally posted by Unregistered
In order to get the "opaqueness" measured, your school needs to have a "Colorimeter" - ask your biology teacher if they have one.

Also, to work out the CU concentration you gotta work in fractions (it's easiest).

1> 10 ml CU, 0ml Water (100%)
2> 10 ml CU, 10ml Water (50% - It's half and half)
3> 10 ml CU, 20ml water (33.3% - it's now in thirds (three 10ml portions))
4> 10 ml CU, 30ml water (half of 25% - it's now in quaters (4 10ml portions).

1. 0.1 concentration
2. 0.05 concentration
3. 0.0333333333 (etc etc) Concentration
4. 0.025 concentration



it seems you no a lot about this subject and i was woundering if there were any other apparatus i would need appart from the colorimetre, egg white and copper sulphate. and are there any safty precautions???????? i really need your help!!! email me:
[email protected]
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#18
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This is my concentration table -:

water Volume of CuSO4 (cm³)
Concentration Time taken
1 2 3
0 1 0.01
0.1 0.9 0.009
0.2 0.8 0.008
0.3 0.7 0.007
0.4 0.6 0.006
0.5 0.5 0.005
0.6 0.4 0.004
0.7 0.3 0.003
0.8 0.2 0.002
0.9 0.1 0.001
1 0 0

-ree

don't know how to get those small measurements though!
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#19
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#19
sorry - you cant read that!

water CUSO4 concentration

0 1 0.01
0.1 0.9 0.009
0.2 0.8 0.008
0.3 0.7 0.007
0.4 0.6 0.006
0.5 0.5 0.005
0.6 0.4 0.004
0.7 0.3 0.003
0.8 0.2 0.002
0.9 0.1 0.001
1 0 0

so does anyone know how to measure out these accuratly?
-ree
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#20
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#20
using a colorimeter doesn't work, the denatured albumen deposits itself unevenly through the solution and because the colorimeter only tests transmission at one point in the tube it aint a fair test and the results are totally meaningless. nice idea, worth putting in your theory section, but it doesnt work in practice!

if anyone wants any more info, email me at [email protected]
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