Food tests - Edexcel IGCSE Biology 9-1

Hello,

I already know the food tests for the different molecules such as starch, glucose, protein, and lipids, but my CGP Revision book details the volumes of the substances I should be testing and provides detailed steps such as adding the Benedict's solution to the starch solution whilst it is in the food bath at 75 degrees Celsius.

These steps seem really unnecessary to learn when I look at lots of 2 marker questions such as 'describe how you would test for glucose' in past papers. However, could somebody enlighten me on whether I actually need to know the details of the experiments or just what solution I use and what colour change occurs?

You could potentially be asked larger tariff questions than two markers about it, even if you can't find any now it doesn't rule out you being asked in the actual exam.

Hello,

I already know the food tests for the different molecules such as starch, glucose, protein, and lipids, but my CGP Revision book details the volumes of the substances I should be testing and provides detailed steps such as adding the Benedict's solution to the starch solution whilst it is in the food bath at 75 degrees Celsius.

These steps seem really unnecessary to learn when I look at lots of 2 marker questions such as 'describe how you would test for glucose' in past papers. However, could somebody enlighten me on whether I actually need to know the details of the experiments or just what solution I use and what colour change occurs?

nah i dont really think all that is necessary. this is all u should know:
glucose- benedicts solution, heat, blue to brick red
starch- iodine, brown to blue black
protein- biuret solution, purple
lipids- im actually not 100% abt this one but i think u just gotta mention adding ethanol and seeing the emulsified white fat layer

Yes, I was sceptical of the other person's response. I don't know why you would have to describe all the steps and volumes; other than the temperature, it wouldn't really matter.

I've learnt the Sudan III stain solution test but yes I remember the use of ethanol as well. I will probably use that in the exam because its simpler

Good luck with exams if you have them coming up.