Qualification > Sciences
Edexcel BIOLOGY Doubts!!!!
~ Miss Relina ~:
why daphnia needs aheart and circulATory system ???
answer all questions in figure provided plz ???
Amelia:
--- Quote from: Relina on April 08, 2011, 11:51:50 pm ---why daphnia needs aheart and circulATory system ???
--- End quote ---
Any organism requires a heart to pump blood. A circulatory system is needed to carry the blood around the body to various organs (for exchange of gases and nutrients). This is done by the help of blood vessels - veins and arteries.
--- Quote ---answer all questions in figure provided plz ???
--- End quote ---
a) When boiled, the vitamin content of the vegetables decreases.
b) Using titration. (The method is provided already in the paper. ::))
Describe how to investigate the vitamin C content of food and drink.
PROCEDURE: Add Vitamin C solution of a known concentration (CONCA), drop by drop, with a pipette, to 2 cm3 of the DCPIP (blue) solution in a test tube. Shake the tube gently after the addition of each drop and continue to add drops until the DCPIP solution is decolourised. Record the exact volume of vitamin C (VOLA) you added. Repeat the procedure and calculate the mean volume.
Repeat the procedure with the fruit juice, containing vitamin C at unknown concentration (CONCB). Record the volume of juice (VOLB) required to decolourise 2 cm3 of the same concentration of DCPIP solution. Note: If only one or two drops of fruit juice are required to decolourise DCPIP, dilute the juice five times and try again.
Using the same technique, compare the vitamin C contents of different food and drinks.
Use the equation below to estimate the concentration of vitamin C in the fruit juices.
CONCB = (VOLA X CONCA) / VOLB VOLA = Volume of vitamin C solution in ml
CONCA = Concentration of vitamin C solution in mg ml-1
VOLB = Volume of fruit juice in ml
CONCB = Concentration of vitamin C in fruit juice in mg ml-
c) You have to write the safety precautions needed to take before you do titration. Gloves, goggles etc...
D)i) Canned vegetables - lose vitamin C during processing. If the canning water is thrown out, even more is lost.
ii) Cutting the fruits and vegetables - Once the protective peels or coverings of fruits and vegetables are cut, the fruits and vegetables begin to degrade and lose vitamin C.
I'll let you do the SAQ6 yourself. ;)
~ Miss Relina ~:
--- Quote from: Amelia link=topic=7382.msg400160#msg400160 date=1302371695
a) When boiled, the vitamin content of the vegetables [i ---decreases[/i].
excuse me can u say to me what does he means to complete the table is there anything missing
c) You have to write the safety precautions needed to take before you do titration. Gloves, goggles etc...
he means safety precautions or any variables to be controls
D)i) Canned vegetables - lose vitamin C during processing. If the canning water is thrown out, even more is lost.
ii) Cutting the fruits and vegetables - Once the protective peels or coverings of fruits and vegetables are cut, the fruits and vegetables begin to degrade and lose vitamin C.
he said fresh friut can u say another thing about the first idea u said
I'll let you do the SAQ6 yourself. ;)
hahahah.....
well anyway thanks i'll tryand post it here
--- End quote ---
~ Miss Relina ~:
--- Quote from: Relina on April 10, 2011, 10:52:17 am ---
--- End quote ---
soorry i wrote in bold as i didnot know how to quote each part separately :-[
~ Miss Relina ~:
http://www.scribd.com/doc/30733651/List-of-Core-Practicals-for-Edexcel-Biology-as-Exam-2010
in exp no.9 is there is a difference between three methods provided ???
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