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edexcel biology unit 2 and 3b

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Reply 40

demdil

anyone know how to prepare an agar solution?

Reply 41

shahlakh

yeah guys u r absolutely right. only two experiments are left: totipotency and mitosis.
Can u tell me what we need to remember in both of these experiments??? please. :smile:

Reply 42

demdil

does anyone have marking scheme for 2009 paper 3?

Reply 43

MarshmallowBob

Original post by demdil

does anyone have marking scheme for 2009 paper 3?

Alll the pastpapers and mark schemes are on edexcels website. lol.

http://www.edexcel.com/migrationdocuments/QP%20GCE%20Curriculum%202000/June09-ms/8BI01_GCE08_Biology_msc_international_20090717.pdf

Reply 44

himi-patel

hey every 1...i am having a small problem..in totipotency..why do we have to make sure that the cotyledons don't touch the agar????.any1 with an answerrr?????

Reply 45

demdil

Original post by MarshmallowBob

Alll the pastpapers and mark schemes are on edexcels website. lol.

http://www.edexcel.com/migrationdocuments/QP%20GCE%20Curriculum%202000/June09-ms/8BI01_GCE08_Biology_msc_international_20090717.pdf

thank you

Reply 46

>>MMM<<

Does anyone know where i can find old SNAB papers from jun 2005 ?

Reply 47

>>MMM<<

What are two ways other than boiling in which vitamin C may be lost from vegetables?

Reply 48

shumen9523

Original post by >>MMM<<

What are two ways other than boiling in which vitamin C may be lost from vegetables?

Storage is one way. The longer the vegetables are stored, the less their vitamin C content. Not sure about the other way but perhaps adding a certain chemical which could react with vitamin C could decrease the vitamin C content as well .....
Hope this helped :smile:

Reply 49

shumen9523

Original post by himi-patel

hey every 1...i am having a small problem..in totipotency..why do we have to make sure that the cotyledons don't touch the agar????.any1 with an answerrr?????

To avoid contamination
Check this website , it's on page 9/15
http://www.scribd.com/doc/79818058/totipotency
good luck

Reply 50

verdikt

Original post by demdil

my opinion; totiopotency may come tomorrow. if it's mtosis they may give pictures and ask which stage the cells are at.. Still we sould do more of "mitosis and totiopotency" than the other experiments. Each year one of the 9 AS experiments came . So now only 2 experiments are left.. we should know the two really well..

What will the next Jun 2013 batch do then? :P

Original post by demdil

anyone know how to prepare an agar solution?

I remember this from an A2 paper. We have to take 3g of agar powder and heat it so that it becomes molten (use of water bath since Edexcel dudes have boners for them; lift the lid to a small extent and pour it slowly into the dish. But this may not be the best answer you may have seen, I'm recalling this from memory :P

Reply 51

shahlakh

well i think the experiment of daphnia may also come. Because this was in specimen papers only but not in the real papers. So do some preparation for that too.

Reply 52

demdil

Original post by verdikt

What will the next Jun 2013 batch do then? :P

I remember this from an A2 paper. We have to take 3g of agar powder and heat it so that it becomes molten (use of water bath since Edexcel dudes have boners for them; lift the lid to a small extent and pour it slowly into the dish. But this may not be the best answer you may have seen, I'm recalling this from memory :P

thanks

btw, i didnt say i am sure that totiopotency and mitosis will come. i only think that they may come as they didnt come before.. after 2013, they will start asking the ones they asked before for another turn .. this is my idea :biggrin:

Are you doing A2 too? İ got B from AS, so i am retaking some units. This summer i have units 2,3,4,5,6 all of them :/

Reply 53

HannyPanda

Can someone state the Dependent, and Independent variables for the Totipotency and Mitosis experiments, and the control? Thank you =) x

Reply 54

verdikt

Original post by demdil

thanks

Are you doing A2 too? İ got B from AS, so i am retaking some units. This summer i have units 2,3,4,5,6 all of them :/

No, I'm doing Bio for the first time, and yes I am doing A2. Hahaha, don't count on that, mate..better be safe than sorry :smile:

Btw, preparation never comes. That's all A2 crap :smile:

Good luck for tomorrow!

Reply 55

demdil

Original post by verdikt

No, I'm doing Bio for the first time, and yes I am doing A2. Hahaha, don't count on that, mate..better be safe than sorry :smile:

Btw, preparation never comes. That's all A2 crap :smile:

Good luck for tomorrow!

thanks. good luck to you too :smile:

Reply 56

MickieJames

Original post by demdil

anyone know how to prepare an agar solution?

Take a bottle containing 15cm^3 of sterile nutrient agar. Liquefy the agar by placing the bottle in a hot water bath (at least 97°C) and allow the agar to cool to about 50°C. Pipette 1cm3 of the bacterial broth into a sterile dish using aseptic techniques. Pour 15 cm^3 of molten agar into the petri dish and replace the lid. Gently push the plate back and forth to mix the bacteria with the agar.

(edited 11 years ago)

Reply 57

MickieJames

Does anyone have the totipotency experiment?

Reply 58

himi-patel

Original post by shumen9523

To avoid contamination
Check this website , it's on page 9/15
http://www.scribd.com/doc/79818058/totipotency
good luck

Thankxx alot..

Reply 59

TheMJCG

Hey good luck everyone, Bio unit 3 is easy we should all do fine, but for some reason I always get stuck on the questions with the implication stuff :s-smilie: