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Emulsion test

Some sees contain lipids. Describe how you could use emulsion test to show that a seed contains lipids (3marks)

someone please correct me if am wrong !
Here is my attempt:

1) Place the seeds into a test tube containing ethanol -shake the test tube
2) lipids dissolves in ethanol- Pour the lipid-ethanol mixture into a clean test tube with a equivalent volume of water
3) White cloudy emulsion is formed. lipid comes out the mixture solution and forms a emulsion of top of the water



+rep :biggrin:
Reply 1
Avatar for Snowfreeze
Snowfreeze
1
Not 100% sure, but wouldn't you have to crush the seeds first before they can react with the ethanol?
Original post by Snowfreeze
Not 100% sure, but wouldn't you have to crush the seeds first before they can react with the ethanol?


Oh you might very well be right actually !! sadly dont have the mark scheme to it so not sure :colondollar:
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Snowfreeze
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Original post by arvin_infinity
Oh you might very well be right actually !! sadly dont have the mark scheme to it so not sure :colondollar:


It says here to crush the sample: http://www.brilliantbiologystudent.com/emulsion_test.html

It doesn't say how you should do it, but I remember my biology teacher saying to use a flat knife :smile:
Was this in the AQA exam? I remember this question from the paper and the generally accepted answer was that you had to crush the seeds first.
I remember this question... I have a feeling it was the very first one on the AQA exam of this year. Am I right? I wrote pretty much what you posted, except I wrote that you need to crush the seeds first.
Original post by Snowfreeze
It says here to crush the sample: http://www.brilliantbiologystudent.com/emulsion_test.html

It doesn't say how you should do it, but I remember my biology teacher saying to use a flat knife :smile:


You defo right then! +repped
am gonna remember the image (crushing the seeds) :P




Original post by Where'sPerry?
I remember this question... I have a feeling it was the very first one on the AQA exam of this year. Am I right? I wrote pretty much what you posted, except I wrote that you need to crush the seeds first.

Not sure cuz am doing OCR

Original post by TheWorldEndsWithMe
Was this in the AQA exam? I remember this question from the paper and the generally accepted answer was that you had to crush the seeds first.


Not sure ..the paper looks like OCR papers (like a v old paper)
Original post by Snowfreeze
It says here to crush the sample: http://www.brilliantbiologystudent.com/emulsion_test.html

It doesn't say how you should do it, but I remember my biology teacher saying to use a flat knife :smile:


You could probably also use a mortar + pestle too (given the seeds are small enough) :redface:
Original post by arvin_infinity
the paper looks like OCR papers (like a v old paper)


That's really weird, the AQA one was a 3 marker as well!
Original post by Where'sPerry?
That's really weird, the AQA one was a 3 marker as well!


One can think AQA doesnt have enough question so it steals from other boards..or maybe they both have problems and using each others :colondollar:
Original post by arvin_infinity
One can think AQA doesnt have enough question so it steals from other boards..or maybe they both have problems and using each others :colondollar:


Ahaha, I had a sudden vision of representatives from the exam boards meeting in some shady alleyway and hastily swapping envelopes containing questions :')
Original post by Where'sPerry?
Ahaha, I had a sudden vision of representatives from the exam boards meeting in some shady alleyway and hastily swapping envelopes containing questions :')


Hahaha yeh representative with so many buddy guards armed with uzi wtf :colone: ...! I can imagine AQA representative sees OCR questions and be like you serious?!? haha what a daft question
Original post by arvin_infinity
Hahaha yeh representative with so many buddy guards armed with uzi wtf :colone: ...! I can imagine AQA representative sees OCR questions and be like you serious?!? haha what a daft question


Oh hell no...

It would be the other way around (OCR telling AQA that they have daft questions :colone:)
they dont react with the ethanol, just dissolve. and in the water it doesnt dissolve so a white precipitate forms.
Reply 14
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cw0161
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well you need to be 100% sure, okay!
Reply 15
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cw0161
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Original post by thegodofgod
You could probably also use a mortar + pestle too (given the seeds are small enough) :redface:




LOL u r sooooooo scientific
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cw0161
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