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Author Topic: CHEM AND BIO HELP AND TIPS HERE  (Read 333107 times)

Offline Ivo

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #1710 on: May 23, 2010, 07:15:18 pm »
Quote from: guMnam on May 23, 2010, 07:12:02 pm
can som1 plz explain me the diff between continous and discontinous variations ???

Continuous variation: influenced by genes and the environment, resulting in a range of phenotypes between two extremes, e.g. height in humans

Discontinuous variation: caused by genes alone and results in a limited number of distinct phenotypes with no intermediates e.g. A, B, AB, and O blood groups in humans.

Hope that helps ;)
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Offline guMnam

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #1711 on: May 23, 2010, 07:17:10 pm »
Quote from: Ivo on May 23, 2010, 07:15:18 pm
Continuous variation: influenced by genes and the environment, resulting in a range of phenotypes between two extremes, e.g. height in humans

Discontinuous variation: caused by genes alone and results in a limited number of distinct phenotypes with no intermediates e.g. A, B, AB, and O blood groups in humans.

Hope that helps ;)
hmm i c Thanks
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Offline CatAly$t

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #1712 on: May 23, 2010, 07:23:39 pm »
Quote from: CatAly$t on May 23, 2010, 06:45:31 pm
is it true that things that didnt came in p6 will come in p3???like reproduction,plant parts and etc...

am i against the sf rules? :-X

y everybody ignored me? :'(
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Offline ambitious94

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #1713 on: May 23, 2010, 07:24:35 pm »
Quote from: thenewkid™ on May 23, 2010, 07:03:34 pm
where is it written?
in the mark schemes. It's usually written for all the general questions..like describe the adv of food additives, use of hormones, issue of world supplies, etc etc...
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Offline Ivo

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #1714 on: May 23, 2010, 07:25:42 pm »
Quote from: CatAly$t on May 23, 2010, 07:23:39 pm
y everybody ignored me? :'(

Hey, of course CIE are entitled to put anything in Paper 3, so study the whole syllabus.  Nitrogen cycle has been one of the questions for the past 3 sessions!
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Offline Ivo

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #1715 on: May 23, 2010, 07:26:26 pm »
Quote from: ambitious94 on May 23, 2010, 07:24:35 pm
in the mark schemes. It's usually written for all the general questions..like describe the adv of food additives, use of hormones, issue of world supplies, etc etc...

There is a glossary of terms used in mark schemes such as AVP, OWTTE in the Oct/Nov 2009 Mark Scheme, take a look ;)!
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Offline ambitious94

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #1716 on: May 23, 2010, 07:27:15 pm »
Quote from: CatAly$t on May 23, 2010, 07:23:39 pm
y everybody ignored me? :'(
Sorry didnt mean to ignore u...
No gratefully, I don't think SF has problems to making predictions....XD
Well, CIE's unpredictable, but I bet they wanna test our knowledge on other stuff....so yea, it's rather unlikely :)
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Offline CatAly$t

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #1717 on: May 23, 2010, 07:28:25 pm »
Quote from: ambitious94 on May 23, 2010, 07:27:15 pm
Sorry didnt mean to ignore u...
No gratefully, I don't think SF has problems to making predictions....XD
Well, CIE's unpredictable, but I bet they wanna test our knowledge on other stuff....so yea, it's rather unlikely :)

thanks ;D :D
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Offline Ivo

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #1718 on: May 23, 2010, 07:28:48 pm »
Quote from: ambitious94 on May 23, 2010, 07:27:15 pm
Sorry didnt mean to ignore u...
No gratefully, I don't think SF has problems to making predictions....XD
Well, CIE's unpredictable, but I bet they wanna test our knowledge on other stuff....so yea, it's rather unlikely :)

Hmm, reproduction or genetics always seems to crop up in one of the topics, and ecology, so get revising on those ;)!
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Offline Ivo

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #1719 on: May 23, 2010, 07:31:23 pm »
By the way, guys, anyone noticed that CIE has put more effort into trying to avoid cheating.  This year is the first time they introduced variants for Paper 6!  Also, I'm guessing more questions will be different between the two variants for Paper 3 (unlike previous years, only 1 or 2 questions were modified)!

I guess it's a much fairer system!
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Offline Ivo

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #1720 on: May 23, 2010, 07:36:31 pm »
Guys, just wondering how many past papers have you done for Paper 3?  I'm getting nervous, and I've only done 2005-2009, argh too little I guess  ::)
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Offline princess12

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #1721 on: May 23, 2010, 07:37:56 pm »
can i tell u chemistry this question
find the empirical formula when 0.5g of H was found to combine with 4.0g of O to form water
can any 1 explain me
urgently reply me as fast as u can
thanks in avance
 :'( :'( :'( :'( :'( :'( :'( :'( :'( :'( ??? ??? ??? ??? ??? :'( :'( :'( :'(
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Offline someone

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #1722 on: May 23, 2010, 07:38:07 pm »
'list the main features used in the classification of the following groups: viruses, bacteria and fungi, and their adaptation to the environment, as appropriate'

im not really sure about this part, could any1 pls correct me if im wrong n add details if possible? thx

virus:
-protein coat
-DNA/RNA strand
-presence of lipids

bacteria:
-plasmid
-no nucleus

fungi:
-cell wall made out of chitin
-hyphae, used to absorb nutrients(is it always from dead organic matters?)
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Offline ambitious94

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #1723 on: May 23, 2010, 07:39:09 pm »
Quote from: Ivo on May 23, 2010, 07:26:26 pm
There is a glossary of terms used in mark schemes such as AVP, OWTTE in the Oct/Nov 2009 Mark Scheme, take a look ;)!
LOOOOOOOOOOL.....how'd u knw I was doin that ppr ;) XD HAHA
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Offline Ivo

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #1724 on: May 23, 2010, 07:40:03 pm »
Quote from: princess12 on May 23, 2010, 07:37:56 pm
can i tell u chemistry this question
find the empirical formula when 0.5g of H was found to combine with 4.0g of O to form water
can any 1 explain me
urgently reply me as fast as u can
thanks in avance
 :'( :'( :'( :'( :'( :'( :'( :'( :'( :'( ??? ??? ??? ??? ??? :'( :'( :'( :'(

Moles of H: 0.5/1 = 0.5       Moles of O: 4/16 = 0.25
Ratio: 2:1

Therefore, empirical formula: H20

Hope that helps :D
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