hey im doing the egg albumen cw and i know exactly how im going to conduct my expreiment but everyone keeps giving different answer about how the egg alubmen is actully denatuerd...i know i NEED to put this in my intro but i dont know how to explain it, and if any one can help i also need a reference becasue i dont think a message board would go down too well. i need to know how the Cu2+ reacts with the COO- group, so any help i soooo welcome. and we've been told that we only have to do the preliminary test if we're not sure if our test would work or not, if this is the case how do i make an accurate prediction, and if i do do one do i need to add my results beacuse surely this is just a planning exercise not an evalution.
which brings me onto the conclusion.....what do we write in it? do we have to do the whole ..."if i repeated this study i would change this... " because we dont actully carry out the study so how can we draw up a results table and graph if we have no results. oh and if anyone knows what a colourimeter measures in then plz let me know. thank uuuuuuuuu. emma xx
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AS biology cw introduction/conclusion watch
- 28-04-2003 09:52
- 28-04-2003 10:40
sorry cant help you...anyone else??
- 04-05-2003 20:05
Colorimeters measure in light intensity, not sure of the units soz. Thanks for the tips, I'm so stuck on this prac!
- 08-05-2003 14:53
The reason why albumin denatures has nothing to do with pH, temperature or anything like that...
Egg Albumen is a globular protein held together by interaction between R groups.
Some of the bonds between R groups are Ionic, i.e. a positively charged R group is attracted to a negatively charged R group and the force of attraction holds the shape of the protein.
Copper sulphate dissociates into Ions in solution. These Ions are also attracted to the charged R groups. The positive Copper ions are attracted to negative R groups, the Sulphate ions to the positive R groups.
These ions neutralize the charge on the R groups so that the R groups no longer bind to each other. This makes the protein uncoil into long strands. Some of the bonds in the protein 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 makes the albumen white.
Instead of using a colorimeter you can compare the amount of albumin that has been denatured with a solution that is obviously denatured for example 0.1 concentration of copper sulphate should be enough.
im not sure how to measure the precentage of the albumen denatured can u help me???
and no colourimeters do not work
- 08-05-2003 14:58
Try comparing it with a mixture of water and albumen if using a colourimeter isnt any good. As for how Cu2+ ions react with the COO- , who said you needed that much detail? The intro\background info only needs to be 150 words max. The coursework is worth 16 marks - you get 3 just for presentation, grammar, spelling and vocab. Any other questions, just email me at [email protected]. I'd better go hand the work in, only 2 hours till the deadline...............
- 10-05-2003 11:23
I think definately use a colorimeter, we did for our preliminary work. put egg white and different dilutions of copper sulphate it test tubes, shook them up 2 mix it. when the colorimeter has 0 on it, it means no light can get through the mixture, when it gives u a reading u can stop cause between those values it is no longer fully denatured as a little bit of light is passing through.
alternativly i guess u cud just hold it up and c if u can c thro it 4 ur preliminary.
hope it helps