AS Biology CourseworkWatch
Copper sulphate is a salt with no electronegative charge but as soon as it is put in with the carboxil groups of the protein it disassociates into CU2+ inons(like in the benadiks test) and attaches 2 the slightly negative hydrogen at the peptide bonds pulling them apart.
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Counts for 16 marks in the OCR version :O
That's not quite how it happens in this case.
What actually happens is heavy metal ions (ie copper in your case) are highly electropositive. they combine with COO- groups and disrupt ionic bonds. thus denaturing the protein.
Hope that helps i'm doing it
Amino acids are able to form a variety of chemical bonds with other reactive groups so as copper is a heavy metal and is highly electropositive (has positively charged particles) when copper ions are added (when we mix the copper (II) sulphate with the egg albumen) they are more electro statically attractive, therefore they bond in favour of the weaker existing ionic bonds, this causes the shape of the protein to be altered and thus the protein is denatured.
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Someone else in my school came up with the following: Egg albumen goes through filter paper. So does water. So, you add 1 ml of albumen to 10 ml of varying concentrations of CuSO4, pass the resulting mixture through filter paper (after shaking), dry out the filter paper and then weigh it. The only problem here is that you won't always get exactly the same amount of egg albumen, even if you do use a 1ml burette (which don't exist, as far as I know), and the filter paper will weigh a different amount every time.
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Egg Albumen is a globular protein held together in the usual manner by interaction between R groups.
Some of the bonds between R groups are Ionic, ie a positively charged R group is attracted to a negatively charged R group and the force of attraction holds the shape of the protein.
CuSo4 disociates into Ions in solution. These Ions are also attracted to the charged R groups. the positive Cu ions are attracted to negative R groups, the Sulphate ions to the positive R groups. They effectively neutralise the charge on the R groups so that the R groups no longer bind to each other. This allows the protein to uncoil into long strands.
Some of the bonds in the portein strand are polar, slightly charged at one end.
H groups are slightly positive, and become attracted to the slightly negative O end of OH groups. As the protein has uncoiled the H and OH groups are free to line up. The resulting hydrogen bonds cause the molecules to stick together. It is this more compact regular arrangement of molecules that blocks the light and turns the albumen white.
Hope that's of some help. Mine has to be in tommorrow.
I was wondering for my introduction do i have to talk about the stuff above. Like what it is and how?
any enzymes involved?
does it need to be timed for fair test?
how ph change scintif kwnol?
and stop cheating by commin on here
Because that is worth a whole lot more marks than this little piece.
i know there is a part on microscope work but do we have to write up lots of essays in the exam???
I'm doing it tommorrow and my teachers aren't helping.
What should i revise and is it hard.
ps please dont post the actual questions- thats cheating.
I asked my teacher and he said this answer would get you full marks for the scientific knowledge section.
Hopes this helps!