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AQA A2 Biology BIOL5 - 17th June 2015

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Original post by JordanL_
Can you get scientific content marks for your plan? Every essay I've done I just lost marks for not enough breadth of content. In my plan I included homeostasis (CO2/temp/blood pressure), endotherms and ectotherms, nervous system (stimuli and response, reflexes, Pacinian corpuscles) plant response (transpiration - closing the stomata, geo and phototropisms) insect response (taxis and kinesis), evolution and adaptation, and antibiotic resistance. But I ended up going on for ages about negative feedback and homeostatic systems even though I knew it was completely irrelevant, I just felt like it wouldn't be complete without an explanation.

In the end all I managed to talk about was a huge amount on why temperature and BP need to be controlled (enzyme denaturation, optimal temp, high BP can cause an aneurysm, low BP can cause tissue death and can be fatal etc), natural selection in response to intraspecific competition for resources and adaptation to the conditions of the environment, and migration to areas with more favourable conditions. I mentioned that different species are adapted for different conditions, specifically thermophiles, and that whales have been migrating in response to climate change (although I didn't get that paragraph finished). I'm hoping this is enough for the marks for beyond A level content, but I don't know. I spent nearly an hour on that essay and didn't get as much done as I'd have liked :frown:

Also wondering if you can lose marks for irrelevant content (as opposed to just not getting any).

Overall I think it was an alright paper, but I missed quite a few questions. They weren't particularly hard, I just couldn't remember a lot of stuff so I missed most of the muscles question, I missed the oestrous cycle stuff (although I don't think there was much on that? Only remember a question about LH?) and didn't do the ratio question because I didn't know which number to divide by which. Also missed the tumour surpressor one and possibly more on the DNA stuff? Can't remember all the questions. Ugh.

Hope the boundaries are low.


I HOPE THEYRE LOW TOO😥😥😥😥😥😥😥😥


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Original post by smoothER
I got 2.27


samee
I struggled on 1b) (why did myosin filaments not binding to each other prevent contraction?) and only realised after the exam that it was about motor proteins. Still, motor proteins aren't on our spec and weren't mentioned in the question, so surely they won't be in the mark scheme. I think I got the general idea - I said since myosin filaments can't bind to each other, they won't be able to move relative to each other for the power stroke to bring actin filaments closer together, or something like that. I didn't express it very well.

I loved the testosterone negative feedback loop question and the DNA methylation one. For the MS one, suggest one reason why MS would lead to lack of control over muscle contraction, I wasn't sure but I talked about nervous transmission being slower along unmyelinated axons so muscle contraction would be slow/delayed. Anyway, there's normally more than one possible answer for those "suggest one reason" questions
Original post by JordanL_
Can you get scientific content marks for your plan? Every essay I've done I just lost marks for not enough breadth of content. In my plan I included homeostasis (CO2/temp/blood pressure), endotherms and ectotherms, nervous system (stimuli and response, reflexes, Pacinian corpuscles) plant response (transpiration - closing the stomata, geo and phototropisms) insect response (taxis and kinesis), evolution and adaptation, and antibiotic resistance. But I ended up going on for ages about negative feedback and homeostatic systems even though I knew it was completely irrelevant, I just felt like it wouldn't be complete without an explanation.

In the end all I managed to talk about was a huge amount on why temperature and BP need to be controlled (enzyme denaturation, optimal temp, high BP can cause an aneurysm, low BP can cause tissue death and can be fatal etc), natural selection in response to intraspecific competition for resources and adaptation to the conditions of the environment, and migration to areas with more favourable conditions. I mentioned that different species are adapted for different conditions, specifically thermophiles, and that whales have been migrating in response to climate change (although I didn't get that paragraph finished). I'm hoping this is enough for the marks for beyond A level content, but I don't know. I spent nearly an hour on that essay and didn't get as much done as I'd have liked :frown:

Also wondering if you can lose marks for irrelevant content (as opposed to just not getting any).

Overall I think it was an alright paper, but I missed quite a few questions. They weren't particularly hard, I just couldn't remember a lot of stuff so I missed most of the muscles question, I missed the oestrous cycle stuff (although I don't think there was much on that? Only remember a question about LH?) and didn't do the ratio question because I didn't know which number to divide by which. Also missed the tumour surpressor one and possibly more on the DNA stuff? Can't remember all the questions. Ugh.

Hope the boundaries are low.


You can get breadth marks from your plan, I'm not sure about scientific content :smile:
Did anyone get the question about the myosin molecules? That really confused me, because it was something about how they wouldn't be able to stick together, I think? I didn't get it, because as far as I know the myosin heads bind to the actin-myosin binding site. There's no myosin binding to myosin is there?
Original post by AmyT997
What did people put for the myosin molecule mutation? and what about the monoclonal antibodies?


I said since myosin filaments can't bind to each other, they won't be able to move relative to each other for the power stroke to bring actin filaments closer together, or something like that. I didn't express it very well.

I died a little when I saw monoclonal antibodies, but the question didn't seem so bad. I said the monoclonal antibody would be complementary to the growth factor receptor of cancer cells so would bind to it and prevent growth factors from binding, so that cancer cells weren't stimulated to grow.
A possible alternative would be that the antibodies bind to the growth factor and prevent it binding to the receptor, but that would actually affect all cells and not just cancer cells, so not sure if they would credit that
Did anyone else make the mistake of thinking the dotted line drawn on the graph for the heart rate question was for the ratio question??? Luckily I realised that the line was drawn to show resting arteriole pressure and not 10(forgot the units) and changed my ratio, but I thought it was a very mean thing to do..
Original post by talkbiology
We will get both - I just checked an MS from June 2011 :smile:


Cool, so is that any ratio simplified from 118:56?

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Did anyone else put you shouldn't use cannabis because they would get high ? 😂
I forgot to write 10(B) when answering the essay... Do you think I will be ok?



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Original post by JordanL_
Did anyone get the question about the myosin molecules? That really confused me, because it was something about how they wouldn't be able to stick together, I think? I didn't get it, because as far as I know the myosin heads bind to the actin-myosin binding site. There's no myosin binding to myosin is there?


Yeah it was confusing indeed...I said something along the lines of myosin molecules not being able to move relative to each other which prevented the power stroke from occurring? It was a bit depressing that that was the first question, tbh. It was one of the hardest questions on the paper I thought :')
Original post by may_1
you again hi

yeah Deffs enough




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Yes me again, how did you find it? Did you do the R?

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Original post by JordanL_
Can you get scientific content marks for your plan? Every essay I've done I just lost marks for not enough breadth of content. In my plan I included homeostasis (CO2/temp/blood pressure), endotherms and ectotherms, nervous system (stimuli and response, reflexes, Pacinian corpuscles) plant response (transpiration - closing the stomata, geo and phototropisms) insect response (taxis and kinesis), evolution and adaptation, and antibiotic resistance. But I ended up going on for ages about negative feedback and homeostatic systems even though I knew it was completely irrelevant, I just felt like it wouldn't be complete without an explanation.

In the end all I managed to talk about was a huge amount on why temperature and BP need to be controlled (enzyme denaturation, optimal temp, high BP can cause an aneurysm, low BP can cause tissue death and can be fatal etc), natural selection in response to intraspecific competition for resources and adaptation to the conditions of the environment, and migration to areas with more favourable conditions. I mentioned that different species are adapted for different conditions, specifically thermophiles, and that whales have been migrating in response to climate change (although I didn't get that paragraph finished). I'm hoping this is enough for the marks for beyond A level content, but I don't know. I spent nearly an hour on that essay and didn't get as much done as I'd have liked :frown:

Also wondering if you can lose marks for irrelevant content (as opposed to just not getting any).

Overall I think it was an alright paper, but I missed quite a few questions. They weren't particularly hard, I just couldn't remember a lot of stuff so I missed most of the muscles question, I missed the oestrous cycle stuff (although I don't think there was much on that? Only remember a question about LH?) and didn't do the ratio question because I didn't know which number to divide by which. Also missed the tumour surpressor one and possibly more on the DNA stuff? Can't remember all the questions. Ugh.

Hope the boundaries are low.


Yes! I'm not the only one who wrote about natural selection and speciation... I was going to write about the breeding seasons and migration of organisms, but I ran out of time.... Sounds like you did pretty decent...

I didn't go into detail about every single homeostasis process... I just gave one which was the blood PH... I linked that a increase in CO2 concentration in atmosphere means more CO2 breathed in, therefore lowers PH level.... causes enzymes denaturing etc... then this is counteracted by increased respiration, so more CO2 removed... and and said it was a example of homeostasis? technically maintains internal envrionment...

I also wrote about the ectotherms, endotherms, kensis, taxes etc... Wrote about how animals can conserve heat and produce it...
also wrote about stimulus(reflexarc)
Original post by talkbiology
I died a little when I saw monoclonal antibodies, but the question didn't seem so bad. I said the monoclonal antibody would be complementary to the growth factor receptor of cancer cells so would bind to it and prevent growth factors from binding, so that cancer cells weren't stimulated to grow.
A possible alternative would be that the antibodies bind to the growth factor and prevent it binding to the receptor, but that would actually affect all cells and not just cancer cells, so not sure if they would credit that


I guess you couldn't say that the antibodies would bind to the receptors which would prevent the growth factors from binding to them? I felt like it was wrong. Monoclonal antibodies really caught me off guard.

Edit - Nevermind, I misread your post! We put the same thing.
(edited 8 years ago)
Original post by talkbiology
I said since myosin filaments can't bind to each other, they won't be able to move relative to each other for the power stroke to bring actin filaments closer together, or something like that. I didn't express it very well.

I died a little when I saw monoclonal antibodies, but the question didn't seem so bad. I said the monoclonal antibody would be complementary to the growth factor receptor of cancer cells so would bind to it and prevent growth factors from binding, so that cancer cells weren't stimulated to grow.
A possible alternative would be that the antibodies bind to the growth factor and prevent it binding to the receptor, but that would actually affect all cells and not just cancer cells, so not sure if they would credit that


I put exactly the same as you (first point) i kind of just ignored the fact that they were monoclonal as if they were monoclonal or not has no effect on their action.
Original post by Thebest786
Cool, so is that any ratio simplified from 118:56?

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Yes :smile:
grade boundaries ImageUploadedByStudent Room1434539499.651774.jpg


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Original post by talkbiology
I said since myosin filaments can't bind to each other, they won't be able to move relative to each other for the power stroke to bring actin filaments closer together, or something like that. I didn't express it very well.

I died a little when I saw monoclonal antibodies, but the question didn't seem so bad. I said the monoclonal antibody would be complementary to the growth factor receptor of cancer cells so would bind to it and prevent growth factors from binding, so that cancer cells weren't stimulated to grow.
A possible alternative would be that the antibodies bind to the growth factor and prevent it binding to the receptor, but that would actually affect all cells and not just cancer cells, so not sure if they would credit that


YES! I said that antibodies bind to receptors on cancer cells to prevent growth factors from binding to it as well :biggrin:

I messed up that myosin filament one.. I just b.s and said the mutation causes a change in tertiary structure and changes shape of myosin head, therefore cannot bind or something along those lines... :frown:
Lol at the cannabinoid calcium ion question, my whole answer was like, "calcium ions wouldn't diffuse into the knob where they wouldn't cause vesicles to fuse with the presynaptic membrane, which wouldn't then release acetylcholine which wouldn't diffuse across the synaptic cleft" etc. Since it asked how it prevented muscle contraction, I didn't know where to stop so wrote a bit too much for that one haha. Lovely question though :biggrin:
Original post by Bustamove
YES! I said that antibodies bind to receptors on cancer cells to prevent growth factors from binding to it as well :biggrin:

I messed up that myosin filament one.. I just b.s and said the mutation causes a change in tertiary structure and changes shape of myosin head, therefore cannot bind or something along those lines... :frown:


How depressing that it was the first question on the paper...

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