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Author Topic: ALL CIE BIOLOGY DOUBTS HERE !!!  (Read 73930 times)

Offline Vampire-Love4ever

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Re: ALL CIE BIOLOGY DOUBTS HERE !!!
« Reply #195 on: May 11, 2011, 11:26:01 pm »
Doubt attached!
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Offline Vampire-Love4ever

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Re: ALL CIE BIOLOGY DOUBTS HERE !!!
« Reply #196 on: May 11, 2011, 11:27:26 pm »
Doubt attached! Please explain Point 11!
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Offline Vampire-Love4ever

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Re: ALL CIE BIOLOGY DOUBTS HERE !!!
« Reply #197 on: May 11, 2011, 11:50:29 pm »
Doubt attached!

Why can't we use a water bath to maintain the temperature? ? ? :S
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Offline Vampire-Love4ever

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Re: ALL CIE BIOLOGY DOUBTS HERE !!!
« Reply #198 on: May 12, 2011, 01:03:00 am »
What role does oxygen play in oxidative phosphorylation?
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Offline Sue T

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Re: ALL CIE BIOLOGY DOUBTS HERE !!!
« Reply #199 on: May 12, 2011, 02:11:58 pm »
Quote from: Vampire-Love4ever on May 11, 2011, 11:09:16 pm
2 doubts attached!

b iii) its jus that if you look at the 2 means -> 0 .156 +/- .001 and 0.197 +/-.013 then you'll see that the upper limit for the first mean (0.156+0.001=0.157) and the lower limit for the second mean (0.197-0.013=0.184) dont overlap - there is a difference between them - so bottom line is there is a difference between the means since their ranges dont overlap ;)

biv) you have to look at the method by which they obtained the means in th table at the begining of th ques. Now they said for each pH, th samples wer monitored at 1 hour intervals for 20hours - so each mean has a degrees of freedom of 19 - now they compared the mean at two pHs so 19x2=38 - if u still dont get it call me
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Offline Sue T

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Re: ALL CIE BIOLOGY DOUBTS HERE !!!
« Reply #200 on: May 12, 2011, 02:23:37 pm »
Quote from: Vampire-Love4ever on May 11, 2011, 11:16:08 pm
Doubts attached!

counting the number of cells on the grid under view gives th no. of cells per 0.04mm2 (since its th area of the grid) If less than half of the cell is in the grid, its not counted. The area 0.04 is multiplied by the depth 0.1mm to give the volume of the grid. this gives 0.004mm3. Now jus count the number of cells under view and divide by the volume (which is identical to multiplying by 250 cuz 1/0.004 = 250) to find the no. of cells per mm3 - mention doing repeats n etc...

next part - it was mentioned in the begining tht th original number of cells was 3thousand. in the table where the mean is - the column heading is thousands of cells per mm3 of culture - so ur mean of 6.2 is actually 6.2 thousand --- now for calculating th percentage increase just follow wat they said takinf th final number as ur mean value and the original number as 3 - thts it
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Offline Sue T

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Re: ALL CIE BIOLOGY DOUBTS HERE !!!
« Reply #201 on: May 12, 2011, 02:30:48 pm »
Quote from: Vampire-Love4ever on May 11, 2011, 11:18:38 pm
Doubt:  my answer was opposite to mark scheme (marked) :S please explain!

see the thing is ur supposed 2 draw conclusions from the graph wether ther is a relationship between the fragmentation index and the conc of this CB-153 thing - now between 60 and 120 u can see a large increase and no overlap of error bars - which supports th theory that th inc in CB causes damage to the DNA - but wen u look at 120 - onwards there is a lot of overlap - so ther cod be no relationship - as in you cant really see anymore wether an increase in CB really causes damage
jus rethink this and look at th answer again - ull b sure 2 get it ;)
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Offline Sue T

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Re: ALL CIE BIOLOGY DOUBTS HERE !!!
« Reply #202 on: May 12, 2011, 03:06:17 pm »
Quote from: Vampire-Love4ever on May 11, 2011, 11:26:01 pm
Doubt attached!
organism 1 has the antibody for antigen X so one line shows up in front of it - organism 2 has th antibody for both antigens so u c 2 lines ( a line forms because a ppt appears due 2 th antigen meeting its antibody.
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Offline Sue T

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Re: ALL CIE BIOLOGY DOUBTS HERE !!!
« Reply #203 on: May 12, 2011, 03:07:55 pm »
Quote from: Vampire-Love4ever on May 11, 2011, 11:27:26 pm
Doubt attached! Please explain Point 11!

see to ensure reliability you have 2 tell them: carry out the experiment in the same area when u repeat it - cuz like other areas myt have some more pollen in the air - its jus 2 produce more reliable results
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Offline Sue T

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Re: ALL CIE BIOLOGY DOUBTS HERE !!!
« Reply #204 on: May 12, 2011, 03:10:05 pm »
Quote from: Vampire-Love4ever on May 11, 2011, 11:50:29 pm
Doubt attached!

Why can't we use a water bath to maintain the temperature? ? ? :S

i think its cuz it myt affect th humidity which decreases th rate of transpiration and affects the rate of movement up the stem ;)
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Offline Sue T

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Re: ALL CIE BIOLOGY DOUBTS HERE !!!
« Reply #205 on: May 12, 2011, 03:13:53 pm »
Quote from: Vampire-Love4ever on May 12, 2011, 01:03:00 am
What role does oxygen play in oxidative phosphorylation?

oxygen acts as the final electron acceptor in the ETC - its necessary cuz it being can combine with the electron which has passed through th ETC and it accepts it (i guess otherwise it wod have no wer else 2 go this lone electron) so wat u need 2 no is without a final electron acceptor those energy changes down ur ETC wont work... there are a few markin scheme answers about this - get 2 no them...

By the way good job attachin ur doubts - saves alot of trouble from jus naming them
and ill answer the specimen 5 questions after monday (cuz i hav an xam n i havent done th ppr) hope thts ok!
cya on wednesday ;)
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Offline Vampire-Love4ever

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Re: ALL CIE BIOLOGY DOUBTS HERE !!!
« Reply #206 on: May 12, 2011, 08:03:35 pm »
JazakAllah Khair for your help, sister!
:D
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Offline Vampire-Love4ever

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Re: ALL CIE BIOLOGY DOUBTS HERE !!!
« Reply #207 on: May 13, 2011, 06:31:45 am »
Quote from: Sue T on May 12, 2011, 03:13:53 pm
oxygen acts as the final electron acceptor in the ETC - its necessary cuz it being can combine with the electron which has passed through th ETC and it accepts it (i guess otherwise it wod have no wer else 2 go this lone electron) so wat u need 2 no is without a final electron acceptor those energy changes down ur ETC wont work... there are a few markin scheme answers about this - get 2 no them...

By the way good job attachin ur doubts - saves alot of trouble from jus naming them
and ill answer the specimen 5 questions after monday (cuz i hav an xam n i havent done th ppr) hope thts ok!
cya on wednesday ;)

It's alright! I'll call you up on Monday (insha Allah) if I have any doubts remaining- hopefully not!
Thank you once again for your help and time!
*I could hug you right now* :D
All the best for Chem! ;)
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Offline Vampire-Love4ever

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Re: ALL CIE BIOLOGY DOUBTS HERE !!!
« Reply #208 on: May 13, 2011, 10:57:20 pm »
Using a respirometer for finding effect of temperature for rate of respiration. Do we use soda lime (KOH) in the apparatus?
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Offline $H00t!N& $t@r

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Re: ALL CIE BIOLOGY DOUBTS HERE !!!
« Reply #209 on: May 13, 2011, 11:29:47 pm »
question!

-Some people have a rare disease caused by a single change in the DNA nucleotide
sequence of the gene coding for lysozyme. The change leads to the formation of an
insoluble protein that has a different structure to the normal soluble lysozyme molecule.

Suggest how a change in the gene can lead to the differences observed between the
normal lysozyme and the changed lysozyme.
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