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

Original post by ConnorB

Well it's not too much extra to learn :P

Does anyone else think that Transcription factors will come up in the pre-release? :smile:

Outline role of transcription factors which lead to higher expression of PRDM16 in BAT than WAT, i'm sensing that...

Reply 4264

ZTSR

Original post by ConnorB

Well it's not too much extra to learn :P

Does anyone else think that Transcription factors will come up in the pre-release? :smile:

Yes yes yes. I think it will previously has in one of the old article questions.
Care to explain what Transcription factors are etcc.

Reply 4265

sunshinesmile10

Original post by iesians

well yeah you are correct but you gave me an EXAMPLE of negative feedback, i need its definition.....

Negative feedback is the mechanism which restores the body temperature to normal when any change occurs - therefore, negative feedback means that the system only kicks into action when a change occurs.
Homeostatic systems involve receptors, a communication system and effectors. The receptors detect the change in level and the effectors counteract the change. Negative feedback only works within limits i.e when the change is small ...

hope this helps

Reply 4266

sunshinesmile10

Original post by ZTSR

Yes yes yes. I think it will previously has in one of the old article questions.
Care to explain what Transcription factors are etcc.

Transcription factors are proteins that control the transcription of genes. Basically, they bind to DNA sites and increase or decrease the rate of transcription. They can be activators or repressors.
An example given in the CGP guide is the thyroid hormone recpetor. Ideally, it slows down the transcription of a protein that controls metabolism. Howver, when thyroxine binds to it, it speeds up the rate, acting as an activator. More protein is produced and increase body temperatur

EDIT: just saw you didnt actually want to know. Sorry, but its out there now

(edited 11 years ago)

Reply 4267

avataraang

Hey guys!

So I have been revising a lot, did lots of past papers, did go through all the spec. points but the one thing always holding me back in biology is the HSW.
I just can't seem to know what the mark scheme wants, especially if you have to apply your knowledge to an unfamiliar scenario (which always comes up!)
Can someone please give me advice on how to overcome this tomorrow? I will give rep points to those who give good advice, as I really need an A/A* in tomorrows paper.
Good luck! :biggrin:

Reply 4268

Original post by PlatypusPigeon

Outline role of transcription factors which lead to higher expression of PRDM16 in BAT than WAT, i'm sensing that...

hmmm would this be a good answer to it :-

certain transcription factors present in BAT initiate the transcription of a gene which codes for the production of PRDM16 by binding to the promoter region in the DNA. the transcribed mRNA is then translated into a functional PRDM16 protein. WAT does not have those transcription factors which are needed for the production of PRDM16 protein.

Reply 4269

PRDM16 is a protien right ? but article says it is KNOCKED OUT ?! only a gene can be knocked out ? i dont get it ! and is there a hormone or somethign which initiates the production of PRDM16 ..?

Reply 4270

Original post by avataraang

Hey guys!

So I have been revising a lot, did lots of past papers, did go through all the spec. points but the one thing always holding me back in biology is the HSW.
I just can't seem to know what the mark scheme wants, especially if you have to apply your knowledge to an unfamiliar scenario (which always comes up!)
Can someone please give me advice on how to overcome this tomorrow? I will give rep points to those who give good advice, as I really need an A/A* in tomorrows paper.
Good luck! :biggrin:

I know it sounds stupid but all you can really do is practice. There are stock answers you can learn (especially when it applies to ethics or human trials) and other question where you just need to analyse the question carefully. Try and highlight keywords that may give hints to the topic they are talking about and from there write all you can! In many questions it's a 4 or 5 marker so just learn the key points and that should get you through, a lot of answers from markschemes where they give 12 possible answers I don't even recognise (like a H:O ratio in respiration?!). The only other thing you could do is correlate similar questions from each past paper and see what they ask for in each one and make stock answers that can be applied no matter what the situation is.

Sorry there's no magical answer to it, it's just applying your knowledge and in most cases revising a markscheme which is stupid if you ask me but that's Snab for you!

Reply 4271

where have you been...............

Reply 4272

rohitbd

8

Can someone explain q2a in june 11 and why the shoot goes right and not left to the light.

Reply 4273

hmmm would this be a good answer to it :-

certain transcription factors present in BAT initiate the transcription of a gene which codes for the production of PRDM16 by binding to the promoter region in the DNA. the transcribed mRNA is then translated into a functional PRDM16 protein. WAT does not have those transcription factors which are needed for the production of PRDM16 protein.

Yeah, that sounds like a good answer, can;t think of much more you could say for it! They'd probably link a long question on to it about translation so just blab about ribosomes and trna and how amazing it is :P

Reply 4274

user3456

gonna sound like a very stupid question lol but is ETC process and oxidative phosphorylation the same thing?

Reply 4275

Original post by user3456

gonna sound like a very stupid question lol but is ETC process and oxidative phosphorylation the same thing?

ETC and chemiosmosis make up oxidative phosphorylation, may be best not the label them as the same! Without ETC you wouldn't have the energy to move protons down the gradient and form ATP from ATPase :P

Reply 4276

Original post by user3456

gonna sound like a very stupid question lol but is ETC process and oxidative phosphorylation the same thing?

oxidative phosphorylation is the major branch out of the two.
IT INVOLVES ETC and chemiosmosis.

Reply 4277

Original post by PlatypusPigeon

ETC and chemiosmosis make up oxidative phosphorylation, may be best not the label them as the same! Without ETC you wouldn't have the energy to move protons down the gradient and form ATP from ATPase :P

i dont get that bit !! why is ENERGY needed to move something DOWN its gradient, isnt it only needed to move somethign AGAINST its gradient ..?hmmmmmmmmmmmm

Reply 4278

pandoraclaire

Original post by rohitbd

Can someone explain q2a in june 11 and why the shoot goes right and not left to the light.

that is EXACTLY what i thought!!! i dont get it surely it makes no sense! I thought maybe they typed the A and B the wrong way round but im sure we would know about it if there was a mistake on a paper :s-smilie:

Reply 4279