egg albumen practical Watch

This discussion is closed.
Unregistered
Badges:
#41
Report 16 years ago
#41
i dont get how to do the dilutions either .. dunno how to get the 0.03 and ones like that .. any help wud be appreciated
jon
0
Unregistered
Badges:
#42
Report 16 years ago
#42
I'm doing the same planning exercise, but with OCR.

These are my concentrations:

5 cc of 0.1 M CuSO4 + 5 cc water = 0.05 M
1 cc of 0.1 M " + 9 cc water = 0.01 M
5 cc of 0.01 M " + 5 cc water = 0.005 M
1 cc of 0.01 M " + 9 cc water = 0.001 M

I am tending to use equal volumes of each (albumen and inhibitor, CuSO4).
Full denaturation will be observed at 0.1 M, so you could use this sample to compare with the others.

Intro. should cover:

1. Protein structure (brief overview)
2. Nature of denaturation

Include the use of colorimeter in your plan.

I would suggest a pipette/ syringe - more accurate. You could transfer those volumes direct into a cuvette, to get a reading.

Remember, it is just a plan, since the practical exam., on Tues. 13th, will not be an extension of this exercise.
0
Unregistered
Badges:
#43
Report 16 years ago
#43
Just wondering which is the dependant and which is the independant variable?

Also whats everyone revising for the exam on tues?

Thanks
0
Unregistered
Badges:
#44
Report 16 years ago
#44
so what would be best, dilusions of 0.1, 0.09, 0.08,.....0.01

or

serial dilusions- 0.01, 0.001, 0.0001
0
Unregistered
Badges:
#45
Report 16 years ago
#45
anyone know where u can find detailed info on the protein structure of albumen??
0
Unregistered
Badges:
#46
Report 16 years ago
#46
You just need to know the general structure of proteins, not a specific protein like albumen.

I have a practical exam on Tues and my planning exercise has to be submitted that morning.

The variables:

Independent: speed of denaturation
Dependent: conc. of CuSO4
Control: quantities (vol) of solns, etc.
0
Unregistered
Badges:
#47
Report 16 years ago
#47
The exam consists of 2 parts:

1. Biochem/physiology from the AS spec (Enz, biol. molecules, etc)
2. Microscopy - drawings, and finding the size of the plant/animal structure.
0
Unregistered
Badges:
#48
Report 16 years ago
#48
what happens in the denaturing of albumen with Copper sulpahte, i need some science for my planning? thanks
0
Unregistered
Badges:
#49
Report 16 years ago
#49
cations from the Cu form strong bonds with carboxylate anions on the amino acids. This causes disruption of the peptide bonds and will transform the shape of the protein's secondary structure.

Cu2+(aq) disrupt the structure of albumen (contains soluble proteins) causing it to re-form as a fibrous protein, which preciptates out of solution and becomes opaque.

I have also played around with the idea of adding NaOH(aq) to the albumen/CuSO4 mixture, to see if protein can be detected (i.e. not denatured). If protein remains, the soln will turn purple.
0
Unregistered
Badges:
#50
Report 16 years ago
#50
God arn't you guy's are getting this way complicated!!!

All we'r doing is adding albumen to distilled water in a conical flask and titrating the CuSO4 into it until cross on paper disappears. Then calc number of moles of CuSO4 used using n=cv. Then using the number of moles/ the vol of water and CuSO4 used to calc the min conc needed, c=n/v!!!

It must be simple, cause i get how to do it!!!

Is any1 else using this approach?

Are there any good sites for back ground info on how denaturation affecs protein, what can denature it and a really simple explaination of four stuctures of protein???

Pinkpanther xXx
0
Unregistered
Badges:
#51
Report 16 years ago
#51
calculations wont get u marks according to the mark scheme i got in fron of me. but it will impress the marker.

try using these headings in the plan:

Intro
Theory (protein structure, denaturation)
Diagram
Method
Safety
Reliability (+ factors to vary/control)
Prediction
Recording results
Further Tests
Bibilography

hope this helps

Now im off to watch Alien on C4. looks like the plan will have to wait till tomorrow - the last day.
0
Unregistered
Badges:
#52
Report 16 years ago
#52
Here's a site that is everything you could wish for:

http://albumen.stanford.edu/library/...sier1991a.html

Some great stuff there!
0
Unregistered
Badges:
#53
Report 16 years ago
#53
ok this has been said several times....using a light sensor or colorimetor is no good as the protein is unevenly distributed through the solution. There are three easy ways to do this.

1. Use a set of controls (as has already been mentioned) you will be able to see if there is no protein left

2. Filtrate the solution so that only the fibrous solid precipitate is left. Then weigh this. This will enable you to theoretically plot a graph of concentration against mass. Concentration along the X axis. What happens is the graph will curve and till it levels off. at this point you have the minimum concentration. You cant plot a graph for ure plan but u can sketch one and this WILL gain u more marks as the examiners have a fetish for graphs (dont ask)

3. once the reaction has happened, filtrate the solution and then add excess copper sulphate to the solution. if protein is still present then you will get more fibrous protein formed. if no protein is present then you wont see anything more. you can then say at what concentration it denatures and which concentration it doesnt.

if u explain one of these fully and well then ull get the marks no matter what u do. personally i opted for method 2 cos it allows me to sketch a graph for my presentation and analysis of results.

hope this helps
0
Unregistered
Badges:
#54
Report 16 years ago
#54
Personally I think that all of u people who r thinkin ur great r a bit sad. Mainly cos of the fact that u dont no wot ur talkin about. The peptide bonds rnt the bonds which r directly affected by the cuso4. So get a life. get the knowledge and have a word with urself in a corner of a darkened room l8ers. Scott the shot aint imprest
0
Unregistered
Badges:
#55
Report 16 years ago
#55
hey ive read all that and im still confused. its due tomaz i havent started it...my ex just was even more of a **** to me and the first guy ive really liked since my ex has just told me he doesnt feel the same...for ****s sake i ahvent even revised for the ****ing practical.
0
snake_n_shades
Badges: 0
#56
Report 16 years ago
#56
ok then, i aint sayin that its the peptide bonds that are affected, how could they be? Its the bonds between the R groups in the secondary structure that are affected

i am great .........if i just keep on telling myself that i might just get decent marks
0
Unregistered
Badges:
#57
Report 16 years ago
#57
please please please please help me someone im getting so worked up about all this what can i write for my background knowledge and prediction nothing seems to sink in and im seriously running out of time i need reasurance from fellow students!!! i feel im gonna fail if i dont get any help please rescue me someone!!!!!!!!!!

LUCI
0
Unregistered
Badges:
#58
Report 16 years ago
#58
hey luci i feel exactly the same!!! -Ellie xx
0
Unregistered
Badges:
#59
Report 16 years ago
#59
This AS bio plan has really upset my timetable. I finished the chem AS & A2 practical plans 5 days ago, but this one has knocked the living daylights out of me: I'm totally sleep deprived in getting it done...and finding time to revise for 4 AS & A2 subjects. The plan is done...though I'm not totally confident about it. I'm past caring about my performance on this exercise. As for the practical in the morning, I have revised all the biochem tests, calc. magnification, etc.

Good luck guys and gals,
J
0
X
new posts

All the exam results help you need

1,763

people online now

225,530

students helped last year

University open days

  • University of Dundee
    Undergraduate Open Day Undergraduate
    Mon, 26 Aug '19
  • University of Aberdeen
    General Open Day Undergraduate
    Tue, 27 Aug '19
  • Norwich University of the Arts
    Postgraduate (MA) Open Day Postgraduate
    Sat, 31 Aug '19

Do you have grade requirements for your sixth form/college?

At least 5 GCSEs at grade 4 (65)
14.16%
At least 5 GCSEs at grade 5 (70)
15.25%
At least 5 GCSEs at grade 6 (90)
19.61%
Higher than 5 GCSEs at grade 6 (185)
40.31%
Pass in English and Maths GCSE (21)
4.58%
No particular grades needed (28)
6.1%

Watched Threads

View All