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AS-Bio - Vit C in fruit practical exam question HELP!!

Can someone help me. I'm struggling with how to start answering this question. I don't know my practicals too well (or any equipment used in the practicals). Any advice would be very helpful!

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Vit C in fruit juice practical exam Q.png

Vit C in fruit juice practical exam Q.png

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Reply 1

BiologyA2Student

Original post by Philip-flop

Is this OCR biology bro?

Reply 2

NNB_Herath

Original post by Philip-flop

Wait...
I shall write the complete answer for you ...give me sometime ok :smile:

Reply 3

Philip-flop

Original post by BiologyA2Student

Is this OCR biology bro?

No it's Edexcel taken from Unit 1 - June 2009 exam (Q6 b)

Original post by NNB_Herath

Wait...I shall write the complete answer for you ...give me sometime ok :smile:

Thaaaaank you! I really appreciate it! :smile:

(edited 8 years ago)

Reply 4

NNB_Herath

Store the Camu Camu fruit before making the juice in both the areas for different number of days.
Then make the juice from Camu Camu fruit by blending it with a mortar and a pestle.
Then titre it with a know volume and concentration of DCPIP solution.
Measure the volume of Juice needed to change colour from Blue to Colourless.
Repeat this with different storage time in both the areas and also repeat at same storage time to get average.
Calibration of DCPIP can be done with a standard solution of Vitamic C
Plot a graph for the two areas and compare
Controlled Variable -
Mass of fruit used to make juice in all trials
Temperature at storage
Volume of DCPIP
Concentraion of DCPIP

(edited 8 years ago)

Reply 5

NNB_Herath

Ask me about other practicals too...
I also do the AS exam this May :smile:

Bio unit 1,2,and 3

Remember to follow me if you find it useful :smile:

Cheers....Good luck for your exams

Reply 6

Philip-flop

Original post by NNB_Herath

Wow, this is very useful!! Do you have any notes about the other practicals? I'm self-taught so don't have much about the core practicals :frown:

Reply 7

NNB_Herath

Original post by Philip-flop

Wow, this is very useful!! Do you have any notes about the other practicals? I'm self-taught so don't have much about the core practicals :frown:

This was not a note
I read your question.....then answered the question with my knowledge without looking at your marking scheme.....
By the way, I study the Practicals from Stafford Valentines Unit 3 book :smile:

(edited 8 years ago)

Reply 8

Philip-flop

Original post by NNB_Herath

Wow, you are very good!!!

Can the Stafford Valentines Unit 3 book be used with the new 2015 Edexcel Bio spec?

Or is there any chance you could scan a few of the pages over to me? I'm in desperate need :frown:

(edited 8 years ago)

Reply 9

NNB_Herath

Original post by Philip-flop

I do not have the book either....my teacher gave me the notes too :smile:

Sorry dude...I would really help you if I could ..........

But ask me questions like this...i will send you the answer like this one... ok...
it is same for all the years...they repeat the same question :smile:

(with slight differences)

Reply 10

Philip-flop

Original post by NNB_Herath

I do not have the book either....my teacher gave me the notes too :smile:

(with slight differences)

Damn. Any chance your teacher has these notes saved as a file that you could send over to me? I'm literally dying in my own panic :frown:

Reply 11

NNB_Herath

Original post by Philip-flop

Damn. Any chance your teacher has these notes saved as a file that you could send over to me? I'm literally dying in my own panic :frown:

He will never even give me a TEXT BOOK :smile:

I once asked him a book and he said he will give the MODIFIED NOTE :frown:

(

Reply 12

Philip-flop

Original post by NNB_Herath

He will never even give me a TEXT BOOK :smile:

I once asked him a book and he said he will give the MODIFIED NOTE :frown:

(

That's so good!! That way all the useless nonsense is cut out!
Am I being cheeky by asking you for these notes? :/ :colondollar:

Reply 13

NNB_Herath

Original post by Philip-flop

That's so good!! That way all the useless nonsense is cut out!
Am I being cheeky by asking you for these notes? :/ :colondollar:

Nopz........but send me questions like that so i will reply and send you a structured answer for all the practicals

Reply 14

Philip-flop

Original post by NNB_Herath

Nopz........but send me questions like that so i will reply and send you a structured answer for all the practicals

Thank you so much.

How about this question?
Caffeine on Daphnia exam 2010.01 Q6b.png

Reply 15

NNB_Herath

Place a know volume of Herbal tea in a slide.
Place the Daphnia in it and allow it to acclimatise for sometime before carrying out the experiment.
Place a cotton wool (to inhibit movement of daphnia) and a heater coil around the Daphnia (to maintain constant temperature-Controlled variable).
Place the slide under the microscope and observe the Daphnia's heart.
Count the beats every 30 seconds using a stopwatch and plot a graph and calculate mean heart rate.
Repeat this to get an average result.

Compare these heart rate data with a control set ( which could have been done before with standard concentrations of Caffeine or White Tea).

Additional Information for these types of Daphnia Questions (not needed for this)

Controlled Variables
Temperature (How to maintain =Using a heater coil around the Daphnia)
Size of Daphnia (How to maintain =using eggs from same mother Daphnia for all trials)
Source of Daphnia (How to maintain =from same place)
Pre-Treatment (How to maintain = (Acclimatising time same for all trials , etc)

(edited 8 years ago)

Reply 16

Philip-flop

Original post by NNB_Herath

Fantastic answer!!!
So do you have "model" answers for these practical questions?

Reply 17

NNB_Herath

Original post by Philip-flop

Fantastic answer!!!
So do you have "model" answers for these practical questions?

nopz.....
The answers differ from question to question so It would be a bit difficult to write the same answer.....try to learn the idea of each experiment