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Edexcel A2 Biology Unit 5 (6BIO5) - 22/06/2011- OFFICIAL THREAD !

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Reply 580
Most of the questions on critical window and brain studies/development won't expect us to regurgitate information. Most likely we're going to have to analyse and interpret data and experiments. For benefits and risks of exercise as well, we will be asked to suggest possible benefits and risks [I guess learning these won't harm!].
Reply 581
Shining*
What does it mean by "off-the shelf" strain of flies?

Oh, and the question about Pan's experiment and what it tells us about the visual cortex development of the mice - do we talk about how axons are able to pass nerve impulses to cells in visual cortex, so synapes used are strenthed?
Or do we talk about how they are similar to humans visual cortex?


Well look at your question. If it asks about mice we talk about mice. If if asks about humans we say that mice and humans are both mammals and both have similar visual cortex and synapses/nerves/neurones involved in visual perception.

You always have to mention the critical period/window for visual development. A lack of stimulation eliminated inactive synapses or reduces the amount of synapses/ neural connections. Length of axons decrease etc. Ocular dominance columns are smaller etc etc
Reply 582
Shining*
What does it mean by "off-the shelf" strain of flies?

Oh, and the question about Pan's experiment and what it tells us about the visual cortex development of the mice - do we talk about how axons are able to pass nerve impulses to cells in visual cortex, so synapes used are strenthed?
Or do we talk about how they are similar to humans visual cortex?


'Off-the-shelf' just means that Miesenbock doesn't have to do extra work to insert foreign genes into the fly brains because they've already been genetically engineered in such a way that it's now easy to inert genes into them. It's kind of redundant meaning it's nothing too difficult to comprehend.
Reply 583
kappleberry
This is the monocular deprivation one. Where they raised a monkey from birth to six months depriving them for any light stilmulus in one eye. And after the six months of light deprivation it was observed that the monkey was blind in the light deprived eye. Deprivation in adults had no effect becase their critical period had already ended.

Page 236 of the snab book.


Has taught us about the relative roles of nature and nurture in brain development - thus, Hubel and Weisels experiments on kittens and monkeys (critical windows) has taught us that external stimulation is important in brain development..

Visual development shows how the effects of nature and nurture where:
Nature: genes control the development of the responsive cells in the visual cortex

Nurture: stimulus from the environment needed during critical window for the correct connections to be made

Hope that helps..
Reply 584
Looking at the sample question on the article kind of quells my nerves.

The questions aren't TOO specific to the article :smile:
Reply 585
Doughboy
Well look at your question. If it asks about mice we talk about mice. If if asks about humans we say that mice and humans are both mammals and both have similar visual cortex and synapses/nerves/neurones involved in visual perception.

You always have to mention the critical period/window for visual development. A lack of stimulation eliminated inactive synapses or reduces the amount of synapses/ neural connections. Length of axons decrease etc. Ocular dominance columns are smaller etc etc


Thanks!
Reply 586
Alot of the questions are to do with Topic 8..
So hopefully, it stays like that in the exam!

This is one exam I am NOT looking forward too! :frown:
Reply 587
shuvo_roy
When the brain is active, it needs more oxygen and so more oxyhaemoglobin is supplied! Since its more active, more respiration and so more CO2 is produced, resulting in more deoxyhaemoglobin production!
I think thats how it works..........someone please help!!


Oxyhaemo. doesn't absorb radio signals and isn't really affected by magnetic fields like Deoxyhaemo. is.

Active parts of the brain have Oxyhaemo. [and so active parts absorb less radio signals/affected less by magnetic field] and show up as lighter images on the screen.
Can anyone sum up the first section of the article for me please.
Im in total loss with that!
Brill thread, just having a break from revising nerves!!
My school gave me this

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Reply 591
kappleberry
Can anyone sum up the first section of the article for me please.
Im in total loss with that!


Okay, here goes LOL

Dancing Worms and Deep Depression

This section of the article simply describes how humans are trying to establish the link between the brain and the mind (particularly how normal life is affected by mental disorders and other diseases such as depression and Parkinson's Disease). We need reliable ways of correcting these horrible problems but those ways are proving to be elusive! :o: Current treatments use "sledgehammer drugs or electrodes". Sledge hammer drugs tell us that the drugs have very bad side effects and they may also trigger other undesirable emotions. Electrodes are hard to handle because of the exact precision needed. It's very very hard to pin point a particular neurone to fire with electrodes. What usually happens is that a bundle of neurones are actually fired and many events follow that (good + bad).

So in order to get better and precise treatments, we need to understand how the brain works...

The article talks about 'dancing worms' and flies. We use these animals because their bodies utilise neurones just like ours do. The ethical implications of using these simple animals come into play here. I won't bother to expand on that now, but please remind me to do so! It's for my own benefit as well.

Scientists discovered that they can use channel proteins to make neurones sensitive to light! This means that we can actually engineer particular neuron types to react to light. Of course, we'd need to understand exactly which neurones do what (imaging techniques e.g. fMRI here). The big limitation is that it's quite hard to get light into the brain.

It's best if we don't use light sensitive compounds because we'd have to genetically engineer brain cells to have the light sensitive compounds [such as the form of ATP]. Besides, our skulls/heads are opaque! So even if we do master neurones and light [which we haven't] problems also arise in determining how we get light into the brain. Hair-thin optical fibres are possible, but how feasible are they for use with humans?

And gene therapy in the brain may be easy, but convincing people to experiment on the BRAIN of all organs is a toughie. Cystic fibrosis is easy[easier] to control with gene therapy cause of the locations of infected organs. The brain is quite a sensitive and important organ and it's location isn't exactly convenient to delve into either.

Keep in mind that even if these therapies are successful, who exactly will be able to use them? Will we be able to afford them? What if people start to abuse the privilege and want to make humans with super brains?

[all the other details of the article just basically describe the works of each scientist etc]

Hope this has helped someone :smile:
Reply 592
AnythingButChardonnay
Found them all and their mark schemes! Enjoy.

:smile: thanx buddy
Reply 593
Original post by &#9829
My school gave me this


No need for that, but thanks anyway. Your school either copied that off of here and gave it to you guys or someone from your school posted the word document here. Or, there could be another explanation :biggrin:
Doughboy
Okay, here goes LOL


Hope this has helped someone :smile:


Doughboy...You're a star! =]
Thank yuu
Doughboy
No need for that, but thanks anyway. Your school either copied that off of here and gave it to you guys or someone from your school posted the word document here. Or, there could be another explanation :biggrin:


ahahaha lol ...
Original post by &#9829
My school gave me this


I haven't got these!
Thankyuus!
kappleberry
I haven't got these!
Thankyuus!

Np :biggrin:

Btw do you guys think the questions could be more like general knowledge instead of definitions and stuff ?
Reply 598
Thanks for those anonymous, anyway though you can get those pictures into .doc

Cheers for the summary doughboy you actually are a ledge. (yes, a window ledge :-P)

But whatcha mean no need for those? I thought they were pretty helpful :eek:
Reply 599
oh yus.

GET IN ENGLAND. 1-0.

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