Author Topic: AS Biology Paper 2  (Read 5979 times)

Offline kratos009

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Re: AS Biology Paper 2
« Reply #30 on: November 17, 2009, 07:36:27 pm »
Yeah cause apparently when i came out of the exam room there were arrows indicating the direction of movement of calcium ions... >:(. It was moving against the concentration gradient out of the cell...apparently...

Offline Dooraven

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Re: AS Biology Paper 2
« Reply #31 on: November 17, 2009, 08:39:29 pm »
Yeah its 100% active transport. Since the arrows indicate which way the ion was moving. I screwed up the last question and I think I lost a mark where "why does the daughter cells have to be genetically identical". I said it prevents mutations but what else?

Offline MaNi_DaDuDe

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Re: AS Biology Paper 2
« Reply #32 on: November 17, 2009, 09:31:59 pm »
what the...

It isn't facilitated diffusion...? O.M.G FAIL >_>

I am pretty sure the question said "It is 1000x LESS concentrated inside..." so is it really active transport?

I thought all ions move via active transport and glucose moves via facilitated diffusion..

@Doorven - for growth and repair of tissues?

Offline vince_24

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Re: AS Biology Paper 2
« Reply #33 on: November 17, 2009, 09:32:27 pm »
Yeah its 100% active transport. Since the arrows indicate which way the ion was moving. I screwed up the last question and I think I lost a mark where "why does the daughter cells have to be genetically identical". I said it prevents mutations but what else?

If you have the same organism, and your daughter cells are different. Your characteristics would change, right..?

Offline kratos009

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Re: AS Biology Paper 2
« Reply #34 on: November 17, 2009, 09:35:44 pm »
I think for that genetically identical cells you just have to say that if genetically identical cells are not produced this would lead to mutation of the DNA, which may result in the formation of cancerous cells due to the mutated DNA. Thats what i put.. ;).

Offline yuedidi

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Re: AS Biology Paper 2
« Reply #35 on: November 18, 2009, 02:12:16 am »
hope i can get A in all four subject lol....
i need 4 A's for my medicine  ::)

Offline kratos009

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Re: AS Biology Paper 2
« Reply #36 on: November 18, 2009, 02:58:39 am »
Ok good luck  ;). Its still a long time away from getting our results, a long wait... :D.

Offline rose107327

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Re: AS Biology Paper 2
« Reply #37 on: November 18, 2009, 10:58:07 am »
yay! i put active transport :D
i got so freaked...the lysosome thing was 4 marks!
what did u guys put for why they raised the temp to 85 degrees??
and what did u write about the cell surface membrane's role?! it was 3 marks!
i just said it folds inwards to engulf materials outside of cell into a vesicle.

Offline kratos009

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Re: AS Biology Paper 2
« Reply #38 on: November 18, 2009, 11:13:13 am »
For the 85 degrees Celsius one they did it to denature the enzyme because the whole point of the experiment was to see when it reached the green colour first. So they needed to kill the enzyme so that it does not keep producing more reducing sugars which would change the colour of the solution of Benedict  ;). And for the cell membrane one you just had to say it consists of receptors, which seek the bacteria via anitgen on bacteria's membrane, and then the bacteria binds to the phagocyte. then the cell membrane engulfs the bacteria via endocytosis.

Offline ilmarien

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Re: AS Biology Paper 2
« Reply #39 on: November 18, 2009, 01:59:10 pm »
I almost gave a "facilitated diffusion" answer and a friend of mine actually answered "facilitated diffusion".  :D

What are the vacuoles/lysosomes??  ??? I can't remember anything about that.

And about the Nitrogen, I thought that the nitrogen will be used by the plant to make protein and proteins have energy values. LOL (Are the leaves even able to?)
I had no idea so I just made a wild guess.

Anyone got confused for the TMP-1 Protein question? I had no idea what I need to mention in that one.

By the way, will the examiners deduct some points if the answers contain bad grammar? I think my brain wasn't working right during the exam and some of the sentences I wrote sounded awfully strange in my head.
« Last Edit: November 18, 2009, 02:08:12 pm by aragornluv37 »

Offline AndrewCedric

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Re: AS Biology Paper 2
« Reply #40 on: November 18, 2009, 02:37:31 pm »
For the TMP 1 .. you only need to trace it out.. Starting from the nucleus blah blah.. replication... transcription... bla blaa.. and sososoosososoo until it reaches the cell membrane.. I am quite positive thats the one they want..

No.. As long as it is still understandable and don't change the meaning, the examiners wont care for your English..

Anybody did Chem P2?? I cant find a post in the forum abt that..

Offline lonelyboy

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Re: AS Biology Paper 2
« Reply #41 on: November 18, 2009, 04:37:55 pm »
Stangely I do not remember any arrows seen. Maybe there was a difference in the variants of the paper done right? One of them had active transport, other had facilitated diffusion because the question specifically said 'the concentration of the calcium ions inside the cell is thousand times less than the concentration outside.' How do these ions move into the cells?

The ions can only move into the cells by facilitated diffusion in that case.

I think there was a variation in the question in both the variants.

That energy level had to do with denitrifying bacteria and decomposing bacteria present in the soil which would increase the energy flow by decomposing amino acids found in tissues (decomposing) and by decomposing the nitrogen compounds to nitrogen (denitrifying bacteria). Mostly denitrifying bacteria as they obtain energy directly by breaking down nitrogen compounds while decomposing bacteria obtain energy by feeding on dead tissue.


For that TMP-1 structure, it had to do with DNA unwinds, mRNA replication, moves out, ribosome, translation, amino acid coded and finally packaged by the Golgi body and leaves via the cell membrane. A number of organelles could be involved from nucleolus to nucleus to ribosomes to Golgi body to cell membrane.

Hopefully the paper was not that bad.

A change in genetical code would result in mutation and would result in different cells hence repair, growth would not be able to take place. In other words, yes characteristics would be changed of the cell.

Offline lonelyboy

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Re: AS Biology Paper 2
« Reply #42 on: November 18, 2009, 04:41:45 pm »
For the 85 degrees Celsius one they did it to denature the enzyme because the whole point of the experiment was to see when it reached the green colour first. So they needed to kill the enzyme so that it does not keep producing more reducing sugars which would change the colour of the solution of Benedict  ;). And for the cell membrane one you just had to say it consists of receptors, which seek the bacteria via anitgen on bacteria's membrane, and then the bacteria binds to the phagocyte. then the cell membrane engulfs the bacteria via endocytosis.


The question was not suggest, it was 'explain.' Suggest would be an assumption as made by you, explanation has a fairly proven reason behind it I assume. Heat was needed to speed up the reaction by providing extra activation energy to the molecules so that colour changes could be observed faster. Without heating, Benedict's solution does not produce results, as we've done in the laboratory. So it was just to speed up the reaction, by providing them with activation energy and increasing kinetic energy of the molecules hence.

Offline kratos009

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Re: AS Biology Paper 2
« Reply #43 on: November 18, 2009, 07:17:57 pm »
Umm, i think in the question they had already stated that the reaction was taking place at temperature around 30 degrees Celsius. That temperature alone would be sufficient to carry out the reaction between the enzyme and the substrate. And anyway the temperature is meant to be kept constant until the point of increase at 85 degrees Celsius. this suggests that they want to find out the rate of reaction using the concentration of the substrate as the variable, which they did. The temperature must be kept constant to obtain a fair result for each of the concentrations of substrate they used. Therefore the only reason in which why they had increased the temperature was to stop the activity of the enzyme in order to have a definite end point to the reaction as it stated in the passage that the end point in which they were observing was the expected green colour, which is fairly early on and would be obtained with the presence of the smallest amount of reducing sugars.
I agree that you had to heat the Benedict at school but most of the time we were just testing the solution itself for the presence of Reducing sugars. In this circumstance there is an enzyme within the solution as well, which is catalysing the breakdown of the sucrose. therefore if you heat the solution too early then the enzyme would be denatured before the reaction has proceeded and no results would be obtained as there would be no reducing sugars present.

This is just my opinion, don't know if its right or wrong....
« Last Edit: November 18, 2009, 08:00:48 pm by kratos009 »

Offline MaNi_DaDuDe

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Re: AS Biology Paper 2
« Reply #44 on: November 18, 2009, 07:34:38 pm »
I agree.

Umm, i think in the question they had already stated that the reaction was taking place at temperature around 30 degrees Celsius. That temperature alone would be sufficient to carry out the reaction between the enzyme and the substrate. And anyway the temperature is meant to be kept constant until the point of increase at 85 degrees Celsius. this suggests that they want to find out the rate of reaction using the concentration of the substrate as the variable, which they did. The temperature must be kept constant to obtain a fair result for each of the concentrations of substrate they used. Therefore the only reason in which why they had increased the temperature was to stop the activity of the enzyme in order to have a definite end point to the reaction as it stated in the passage that the end point in which they were observing was the expected green colour, which is fairly early on and would be obtained with the presence of the smallest amount of reducing sugars.

This is just my opinion, don't know if its right or wrong....