Author Topic: Edexcel BIOLOGY Doubts!!!!  (Read 132281 times)

Offline Saladin

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Edexcel BIOLOGY Doubts!!!!
« on: May 08, 2010, 06:52:52 am »
Hey you all, please post all yo bio doubts hea!

Offline Tammy

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Re: Edexcel BIOLOGY Doubts!!!!
« Reply #1 on: May 09, 2010, 07:21:46 am »
What do we have to study for Biology unit 3???!! There is nothing to study for it... ??? ??? ???

Offline T.Q

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Re: Edexcel BIOLOGY Doubts!!!!
« Reply #2 on: May 09, 2010, 10:00:05 am »
What do we have to study for Biology unit 3???!! There is nothing to study for it... ??? ??? ???

try this https://studentforums.biz/index.php/topic,7364.0.html
No Matter What Happens In Life , Just Don't Lose Hope :)

Offline Summer :]

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Re: Edexcel BIOLOGY Doubts!!!!
« Reply #3 on: May 09, 2010, 05:19:30 pm »
What do we have to study for Biology unit 3???!! There is nothing to study for it... ??? ??? ???
All the practicals in unit 1 and 2
-daphnia's experiment
-cell permeability experiment
-vitamin c experiment
-enzyme controlled reactions experiments
-root tip squash experiment (observing mitosis)
-investigating totipotency in plants (tissue culture)
-mineral ions deficiency experiment
-antimicorbial properties of plants experiment
- plant fibres experiment
thats all
and some background of some unit 1 information such as CVDS and their risks, Genetic diseases (like CF) and genetic diagrams, what else..
genetic screening
(scan through)
for unit 2, basically you're taking the exam now in june so you know the information/facts there..

Offline Blizz_rb93

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Re: Edexcel BIOLOGY Doubts!!!!
« Reply #4 on: May 09, 2010, 08:10:17 pm »
I have this question regarding Beetroot pigments..

 Suggest why it was necessary to rinse the beetroot discs before they were added to the distilled water.

Offline T.Q

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Re: Edexcel BIOLOGY Doubts!!!!
« Reply #5 on: May 09, 2010, 08:43:05 pm »
I have this question regarding Beetroot pigments..

 Suggest why it was necessary to rinse the beetroot discs before they were added to the distilled water.


to remove excess dye
No Matter What Happens In Life , Just Don't Lose Hope :)

Offline M-H

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Re: Edexcel BIOLOGY Doubts!!!!
« Reply #6 on: May 09, 2010, 08:45:20 pm »
I have this question regarding Beetroot pigments..

 Suggest why it was necessary to rinse the beetroot discs before they were added to the distilled water.

to wash away excess dye

Offline Blizz_rb93

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Re: Edexcel BIOLOGY Doubts!!!!
« Reply #7 on: May 09, 2010, 08:54:01 pm »
ahh okay then =) thank you

Offline future_scientist

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Re: Edexcel BIOLOGY Doubts!!!!
« Reply #8 on: May 10, 2010, 05:55:52 am »
i need HELP in some exp's.
1-totipotancy in plant cells
2-viewing mitosis
"i don't know how should i write them in the exam"
 ??? :(

Offline M-H

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Re: Edexcel BIOLOGY Doubts!!!!
« Reply #9 on: May 10, 2010, 08:24:44 am »
i need HELP in some exp's.
1-totipotancy in plant cells
2-viewing mitosis
"i don't know how should i write them in the exam"
 ??? :(
https://studentforums.biz/index.php/topic,4830.0.html
go here..
all the v best!

Offline Uchia

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Re: Edexcel BIOLOGY Doubts!!!!
« Reply #10 on: May 10, 2010, 09:36:46 am »
help me in the following questions please

1) list 3 precaution which would be needed when doing the vit c experiment
i know two of them 1) conq and volume of DCPIP  2) same conq of vit c by using same solution

2) give 2 ways other than boiling which vit c could be lost?
I know 1) leaving it exposed to air

3)Callus tissue develops into either shoots or roots depending on the relative concentration of the plant
growth regulators used. Use your knowledge of genes to suggest how these plant growth regulators
determine the type of plant tissue formed.

last
could you tell how to ensure the reliabilities when doing the experiments such as betroot, vit c, tensile strength, mitosis, etc...


Offline M-H

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Re: Edexcel BIOLOGY Doubts!!!!
« Reply #11 on: May 10, 2010, 10:12:55 am »
help me in the following questions please

1) list 3 precaution which would be needed when doing the vit c experiment
i know two of them 1) conq and volume of DCPIP  2) same conq of vit c by using same solution

2) give 2 ways other than boiling which vit c could be lost?
I know 1) leaving it exposed to air

3)Callus tissue develops into either shoots or roots depending on the relative concentration of the plant
growth regulators used. Use your knowledge of genes to suggest how these plant growth regulators
determine the type of plant tissue formed.

last
could you tell how to ensure the reliabilities when doing the experiments such as betroot, vit c, tensile strength, mitosis, etc...


juice is expired...vit c content will b less

reliability-beetroot...um, all the beetroot discs gta b of same size surface area thickness
volume of distiled water in wich theyr kept needs to b the same
if the experiment is done to see the effect of conc of alcohol-the temp needs to be fixed.

Vit. C-
conc. and volume of DCPIP needs to b kept constant
once a glassware-pipette/burette used, if it has to be used again then it needs to be washed before used and then the solution can be taken in it.

mitosis-
all root tips nearly of same size
making sure the nucleus is stained and not the cytoplasm.this' done by placing the slide on the tissue paper, fold the tissue over and gently press so that all the stain is absorbed.

that's all i can think of for now....ur 3rd question..um i don't know much..i can guess but don't wana say unless im v sure.
hope that helps
:)good luck...

Offline wrongaccount

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Re: Edexcel BIOLOGY Doubts!!!!
« Reply #12 on: May 10, 2010, 11:22:34 am »
I dont understand the flow chat things ): ):
for instance in JAN 2010 Q2 part a)  how am i suppose to draw that flow chart ??

and if there is any other flow charts in previous papers please let me know

Offline Uchia

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Re: Edexcel BIOLOGY Doubts!!!!
« Reply #13 on: May 10, 2010, 11:38:06 am »
for the flow charts its easy you just need first to know how the experiemnt is done for example in jan
the question was about weithering before you draw the flow charts you should already study what he did cz its included in the syllabus and i think you will find it in how science works in your text book

Flow charts

1) start     2) reasearch, gathering information and compare 3) test drug on small number of healthy people  3) record effects 4) see if there is death 5) test on small number of people with disease 6) record effects 7) increase/decrease the dose of the drug 8) record effects and compare to find the appropriate dose 9) approval and sale

Offline Assi1993

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Re: Edexcel BIOLOGY Doubts!!!!
« Reply #14 on: May 10, 2010, 03:30:40 pm »
Suggest why Daphnia needs a heart and circulatory system