Author Topic: IGCSE Biology Paper 3  (Read 23475 times)

Offline Friends

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Re: IGCSE Biology Paper 3
« Reply #15 on: June 09, 2009, 05:30:06 am »
dry mass, i put measure the amount of solution uptaken by the plants., and then subtract from original. I think its wrong.

I wrote the Same. I think its Right.

Offline thukon

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Re: IGCSE Biology Paper 3
« Reply #16 on: June 09, 2009, 05:30:28 am »
thank god. But i hope i dont get that bad a percentile. I screwed up in some other questions too.

Offline annie_angel

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Re: IGCSE Biology Paper 3
« Reply #17 on: June 09, 2009, 05:33:20 am »
DRYMASS is to calculate the mass of an organism whn all da water is removed....u rote da complete opposite!!
Dont tell God how BIG your storm is...;tell your storm how BIG your GOD is.^_^

Offline aquarian93

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Re: IGCSE Biology Paper 3
« Reply #18 on: June 09, 2009, 05:33:45 am »
the liver cell, i rote cell membrane as well. ws gna do cytoplasm and nucleus, bt instead i did cytoplasm for the thing in da middle and vacuole around cuz it din look like a nucleus (which is usually very dark and doesnt hav dots) and the thing around was plain (like vaculoes, it din hav dots like cytoplasm does)

so yea, i dunno

Offline thukon

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Re: IGCSE Biology Paper 3
« Reply #19 on: June 09, 2009, 05:34:50 am »
@ annieangel. Yeah i know what dry mass is. Thats why i subtracted the amount of water that the plant uptakes.

Offline Friends

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Re: IGCSE Biology Paper 3
« Reply #20 on: June 09, 2009, 05:36:21 am »
DRYMASS is to calculate the mass of an organism whn all da water is removed....u rote da complete opposite!!

Wait.. What I wrote is this:
Take the initial volume of solution then subtract the final volume of solution (1) from it.
Now take the mass of radish and subtract the answer we got in (1)

Offline aquarian93

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Re: IGCSE Biology Paper 3
« Reply #21 on: June 09, 2009, 05:36:53 am »
over all ws it easy, hard? how do u think the threshold will be?
i thoght it was very long, one thing. it was very "geo" like, u noe sooo many lines for each questions wid like 5 marks and all, weird, haha.
bt it was ok for me i gess

Offline thukon

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Re: IGCSE Biology Paper 3
« Reply #22 on: June 09, 2009, 05:38:00 am »
DRYMASS is to calculate the mass of an organism whn all da water is removed....u rote da complete opposite!!

Wait.. What I wrote is this:
Take the initial volume of solution then subtract the final volume of solution (1) from it.
Now take the mass of radish and subtract the answer we got in (1)
I wrote the same thing.

Offline Friends

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Re: IGCSE Biology Paper 3
« Reply #23 on: June 09, 2009, 05:38:57 am »
I totally messed up with the Natural selection question[5mks]
But the paper was little bit hard compared to 2008.
Threshold will be 50/80 for A

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Re: IGCSE Biology Paper 3
« Reply #24 on: June 09, 2009, 05:39:38 am »
the water that the plants have taken up is not the only wet mass they have. The water has to be removed completely

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Re: IGCSE Biology Paper 3
« Reply #25 on: June 09, 2009, 05:41:48 am »
the water that the plants have taken up is not the only wet mass they have. The water has to be removed completely
Yeah I know.
But as they used the same raddish for 6weeks. We cannot dry it. So the Best option Would be what we wrote.
 ;D ;D ;D ;D ;D

Offline aquarian93

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Re: IGCSE Biology Paper 3
« Reply #26 on: June 09, 2009, 05:42:16 am »
i jus sed withdraw/dehydrate the plant.
ws a hard question.

Offline Mirzaa

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Re: IGCSE Biology Paper 3
« Reply #27 on: June 09, 2009, 05:42:42 am »
yes its rong...u just put da bacteria in a fermentor;add feedstock;it respires and reproduces;and u get the product...it waz a repeated question...plz correct me if i m rong

NICE!! thats exactly what i put, wrote about the fermenter, but with much more detail :)

Offline Mirzaa

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Re: IGCSE Biology Paper 3
« Reply #28 on: June 09, 2009, 05:45:12 am »
Liver cells - Nucleus, Cytoplasm, and cell membrane. I hope.
Yeah, hepatic portal vein and ileum
dry mass, i put measure the amount of solution uptaken by the plants., and then subtract from original. I think its wrong.

yea thats wrond dude.... uve gotta bake the radish plant to find the dry mass..!

nid404

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Re: IGCSE Biology Paper 3
« Reply #29 on: June 09, 2009, 05:47:24 am »
the water that the plants have taken up is not the only wet mass they have. The water has to be removed completely
Yeah I know.
But as they used the same raddish for 6weeks. We cannot dry it. So the Best option Would be what we wrote.
 ;D ;D ;D ;D ;D

who said the radish used is the same for the weeks. It's not possible...and im sorry cuz to find out dry mass u need to kill the organism.

I'll put down exactly what the book says..take a look

Dry mass is often used as a measure of growth, because wet mass varies from day to day. The value for dry mass is obtained by drying out the organism in an oven, but this involves killing it.