A-level BIOCHEMICAL TESTS- test for starch, reducing sugars, non-reducing sugars, proteins, lipids
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- Опубликовано: 9 июл 2024
- Learn the biochemical tests for A-level biological molecules topics. Most of these biochemical tests are also on the GCSE specification too. Learn how to test for starch, proteins, lipids, reducing and non-reducing sugars.
I have taken time-lapse videos of each experiment and photos so you can see the practicals in actions- hopefully, this helps!
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I left my book at school, thank you
You're welcome 😊
A friend took mine and tomorrow is my CIE AS LEVEL EXAM😂
Keep doing what you’re doing. The clarity you produced is amazing
Thank you so much 😊 Means a lot to know the videos are helping.
@@MissEstruchBiology swe
I was sick from school and I miss this lab experiment but your video help me to get caught back up and understand everything. Thank you so much and keep being you.
Amazing 😃😃 So pleased it helped you to catch up.
Me too❤😊
I am a private student and self studying looking for a complete career change, I have found your videos that have been an amazing complement to the AQA text book. I watch your videos before studying the topic and it just makes so much more sense. Being a private student, it is tough to get into a lab, so thank you for these brilliant videos. I understand how much time they must take to compile. Thank you!
You are so welcome! I'm so pleased they are helping you 😊😊
I love how you cover every spec point and put the mark scheme answers in bold. Thank you so so much!!
Thank you! So glad you find it helpful the way it's presented. I try to keep it concise and linked to marking points to help with efficient revision.
thank you so much for this video Miss Estruch!! the bit about why the colour change starts at the top is so cool :) and the practical video is so helpful since we can't do practicals at the moment :(
Really glad you found it helpful as a replacement for actually doing the practical.
Who is mean enough to dislike these? They are amazing and so helpful, Thankyou so much 🙏
haha thank you 😊
So pleased you find them helpful. Good luck with your exams!
This channel is underrated
You are legit the eliot rintoul of A level biology
Great vid thank u!
Thank you so much 😊😊
Hope the videos help your studies!!
thanks miss Estruch, you are amazing. I was so confused, but when I watched your video, you clarified everything
So pleased it helped you 😊😊
should be illegal to explain things as good as you do aha, some serious talent for teaching there
😆😆 aww thank you!!
Excellent video for quick revision... thanks!
Thank you so much, for some of us who are writing GCE.
You're welcome 😊
thank you so much for this video Miss Estruch
You are so welcome! I hope its helpful :)
Excellent - great to share with students who have either not done or have forgotten food tests!
i know you commented this ages ago, but do we need to add water to the sample along with benedicts?
Hello Miss!!!!! Thank you so much for the video :)
You are very welcome! Really pleased it have helped you.
The video is mazing so i have downloaded it. Thank u very much.
Great video, thanks so much for all the tests in one and the final summary!!!
Thank you!
Thanks a lot Miss. It helped a lot...
you're so welcome
Thank you so much...i even learnt beyond my textbook
So glad the video helped 😊
This woman is out here saving lives😭
Wow this is helpful thanks so much God bless you abundantly ❤❤
Thank you for amazing video 🙏🏻❤
You are so welcome!
THANK you so much .
Hope it helps 😊
Words can’t describe how much I love this women
😂😂😂 glad the videos are helping
Hi Miss, do we have to know specific measurements of how much reagent we have to add. Like do we have to say “add 2cm3 of Benedict’s reagent to the test tube”
Hi, miss! What changes would you make to obtain semi-quantitative results, please?
Which acid and alkali have you taken for the non reducing sugars?
Very helpful
So glad it helped you 😊
Lovely work, this will be helpful for my tests.
Thanks!
~Mustafa Dafalla.
You're so welcome!
can please elaborate on how much you're adding like how many
drops of acid
Do we need to know why the colour change occurs at the top of the solution first for the exam ? is that on the spec ? Amazing videos ! I'm watching them all before my exams this year , I haven't been able to go to my lessons but have still got As thanks to you !!
Hey not on the spec, but an example of an application question
This is extra work given by my teacher, and wooh 😅 this is hard im currently in year 8 and this helped tyssm !!❤❤
Yay,glad it helped 😁
Hi from Pakistan, thanks for saving me. I have shared your this consolidated biochemical test video with my FSc ( high school's students) as I was guilty I couldn't deliver them enough in my practical class.
Keep up good work . N I would like to suggest u a few more topics along with textbook material that needs 3D demonstration and practical demonstration. If u appreciate it, u may create a video on it. Stay blessed ❤
Hi :)
I'm confused. In my book it says that for the buiret test for protiens that you need to add Sodium hyroxide solution to the test sample, then add Copper(II) sulfate solution.
I'm not sure, in an exam situation, what to put to get the marks. Your explanation or the textbooks, OR is it the same thing?
Thanks :))
Hello,
Those are the chemicals that biuret is made of, so you can say either in the exam 😊
Hi Miss Estruch,
Firstly thank you for these videos, they're amazing!!
I was just wondering if we need to know the names of the 'acid' and 'alkali' in the tests- like non-reducing sugars?
Hello,
No, its not specified on the specification. Just need to know it is 'boil in acid' and then add alkaline to make slightly alkaline as that is required for Benedicts
@@MissEstruchBiology Ahh ok, thanks so much!
Hey miss, is it fine if i use some of the picture of your videos for my flashcards, non-commercial use. I would really like to take pictures of your tests and a few diagrams for my anki deck
Hey yeah of course, that sounds like a good way to make flash cards
I did experiment but I didn't understand coz our lab supervisor didn't explain it properly but thanks for the help from this video.
Happy to help 😊
Thanks so much for the video! Really helpful. I have a small doubt if you could answer. What exactly is the reagent in the lipid test? Is it ethanol or distilled water?
There isn't a single reagent, both are required and both are worth separate marks in the exam.
Hope that helps 😊
Thank you!
And also one more thing, is emulsion and turbidity the same thing?
no, turbidity is a measure of cloudiness, but emulsion is the technical name for a fine dispersion of minute droplets of one liquid in another in which it is not soluble or miscible.
cheers
Hi Miss, for the test for proteins, do we just need to say ‘add Biuret solution’, because I was doing some questions from the revision guide and in the answers it says ‘add a few drops of sodium hydroxide solution, then add some copper (II) sulphate solution’.
Hello,
For AQA they accept either answer, so I always say biuret as it's less to remember 😊
@@MissEstruchBiology ok thanks Miss
do we not need to specify which acid and alkaline to add for the non reducing sugar test?
Hello,
For AQA it doesn't specify that you need exact names of the acids and alkaline.
@@MissEstruchBiology Okay thank you very much, I looked them up and they arent hard to remember.
Hello miss , I know this isnt part of the video , but im a 2 year a level student , i have my A LEVEL paper 1 exams in about 3 days , should i go through AS paper and A LEVEL PAPER , or should i just go through a level past paper
Hello,
It depends how much time you feel you have. The A-level papers should be a priority, but the AS papers do have a lot of really good maths questions and practical questions in too that will be helpful. If you have time, then yes I would recommend you do.
Good luck!
@@MissEstruchBiology ok thank you soo much :)
Hi Miss,
just wondering about the test for protein, my textbook says to add sodium hydroxide and then copper ii sulfate and observe the color change. just wondering what I should write in an exam?
that is a long description of the biuret test. Both would get a mark, but biuret is much quicker to write
@@MissEstruchBiology Thank you soo much!!!
Do you know what Reducing sugars we have to learn for AQA are?
glucose, fructose, galactose, maltose and lactose 😊
Sucrose is non reducing
@@MissEstruchBiology thank youuuu
Hello. This video explained the biochemical tests really well, thank you! May I ask that I don't still get why the non-reducing sugar (sucrose) is not able to reduce the copper sulphate. Lactose and Maltose are also disaccharides, so how is this different to Sucrose, may I ask why aren't they non-reducing sugars. I hope that makes sense. Thank you Miss Estruch.
Hello,
Its because of the monomers sucrose is made of.
Because it contains fructose, unlike the other two disaccharides, it forms a bond that prevents it from reducing Benedicts.
Have a look at the pics in this link images.app.goo.gl/Nmo2ErcbUMPaURRS8
Hope that helps 😊
Just wondering, were we supposed to know oil is a lipid? Just a bit concerned because I didn't really know that
Thank you!
yes, it's an unsaturated fat
may i ask how is the starch orange in colour
Starch is colourless. It is the iodine that is orange, and it turns blue/black in the presence of starch
Thanks mam
you're welcome 😊
Whats the use of distilled water in tests ?do we use distilled water As a control? To compare other tubes with its results
yes that's it! It's the control to show it was the test substance causing any changes seen
Hi Miss Estruch .Firstly thanks for the fascinating videos .I would like to ask about the negative result on lipids .Hmm what's the negative result
The negative would be no white emulsion. There isn't a set colour to describe as ethanol is colourless.
Okay thanks
Thanks for that madam biology am kyobs science because I knew what I was eating
I always thought Biuret was pronounced Bee-oooh-ray. Thats what I get from learning it by myself from a Textbook and no other input (until I discovered your channel of course) :)
Very French pronunciation of you !
@@MissEstruchBiology Haha so true.
greatest channel of all time
☺☺ aww you're too kind, thank you!!! Hope the videos are helping you.
❤❤
🙂
Hey
👋
this is wrong
for protiens add NaOH then Copper Sulphate and if protien is present it turns purple
Hello, that's what biuret reagent is. For most UK exam boards, they require the name of the reagent rather than the chemical composition
@@MissEstruchBiology sorry its cus i do AQA
3:46 if you didn't have file explorer open you would have doxxed your self
Bit weird
@@keetanjohal3559 nah but her school logo was there im just saying
@@Wojbest_YT hahaha lmao join me i will find her school
@@Wojbest_YT Nvm she goes to woodford county high school for girls
@@keetanjohal3559 nah u cant that would be L rizz
I hope to speak Arabic because I don't understand very clear
ah sorry, I only speak English
But can you explain for me food and it's constitunets
Also digestion of starch
@@MissEstruchBiology digestion of proteins and lipids
@@MissEstruchBiology and activity of enzymes because I have exam tomorrow and I don't understand any thing from my teacher because she 60years old
Can't you speak Hind mam?