[verdikt]

Hey guys, can anyone help explain me the induced fit theory?

I get that the substrate influences the change in the shape of the active site of the enzyme but this only happens when it binds to it. So doesnt that mean the substrate has to be specific in the first place to begin with?

[Ataraxian-Walker]

(Original post by cisne)
http://www.mystudytable.com/biology-...-2008-t92.html
http://www.mystudytable.com/biology-...-2007-t95.html

check this out....hope this helps...best of luck

Thank You (:

[Ataraxian-Walker]

(Original post by verdikt)
Hey guys, can anyone help explain me the induced fit theory?

I get that the substrate influences the change in the shape of the active site of the enzyme but this only happens when it binds to it. So doesnt that mean the substrate has to be specific in the first place to begin with?

Think of it as a lock and key model. There are specific substrates that combine to a specific enzyme. The theory basically states that both enzyme and active site change shape so only a specific substrate bind to the enzyme. And creating the wanted products that the reaction creates.

[Kabelan1]

Specimen Past Paper, and the Jan 2012 paper, for those who don't have it.

http://www.scribd.com/doc/53592381/GCE-Biology-6BI01

[Kabelan1]

Does anybody have any idea of what core practical will be in this upcoming Unit 1 paper?

[verdikt]

(Original post by Ataraxian-Walker)
Think of it as a lock and key model. There are specific substrates that combine to a specific enzyme. The theory basically states that both enzyme and active site change shape so only a specific substrate bind to the enzyme. And creating the wanted products that the reaction creates.

When do they change its shape; is it when it starts to bind to the enzyme or when its already bound to the enzyme?

[Ataraxian-Walker]

(Original post by verdikt)
When do they change its shape; is it when it starts to bind to the enzyme or when its already bound to the enzyme?

The enzyme will change its shape until it is completely complementary to the substrate to activate the enzyme-substrate complex.

[meow_56]

can any1 upload the cgp revision guide it will help alot

[ummm]

The "describe this graph" questions are soososososososooo boring.

[bestfriends33]

Im finding it so difficult to answer the graph questions.. that's where I loose all the marks!

[himi-patel]

umm i need help in the description of the germline genetherapy..how does it go????

[Kabelan1]

(Original post by himi-patel)
umm i need help in the description of the germline genetherapy..how does it go????

Involves changing the alleles in the sex cells. This means that every cell of any offspring produced from these cells will be affected by gene therapy and won’t suffer from the disease. But germ line therapy in humans is currently illegal though.

[IchHabDichLieb]

can someone tell me how to work out question 8b (iv). thanks

[himi-patel]

(Original post by IchHabDichLieb)
can someone tell me how to work out question 8b (iv). thanks

if you check out the points in the graph......the bar graph is overlapping so dont get confused on how to read the graph...just read it direct,,,,in usa for males itz 72 and females itz 68...so ratio is 72:68....now if u keep dividing the numbers ,,to the simplest ratio you get 18:17

[Nas.]

Only 2 days left.
Anyone got any idea of how I should revise?

I haven't really done much 'full-on' revision, just some here and there, and now I think I may get a D or an E

Can anyone tell me how to revise carbohydrates, lipids, protein and DNA, in such short space of time I really find those questions hard

[Kabelan1]

(Original post by Nas.)
Only 2 days left.
Anyone got any idea of how I should revise?

I haven't really done much 'full-on' revision, just some here and there, and now I think I may get a D or an E

Can anyone tell me how to revise carbohydrates, lipids, protein and DNA, in such short space of time I really find those questions hard

Try and make notes on each topic, using the book provided by edexcel, or a revision guide, or even the internet.

After that use the notes, try and understand it. Once you do understand it try and memorise it. I do this with most of the topics. But, just remember to understand it before memorising it.

Btw I use the specification to check of all the things I have to know.

Here's a link below

http://www.edexcel.com/migrationdocu...4%20250510.pdf

The checklist for unit 1 and starts on page 21.

It may be that this method does not work for you, you may be suited to making quick flash cards.

2 Days should be more than time enough to learn those topics.

[Ataraxian-Walker]

What are the ethical and social issues of genetic screening? :/

[verdikt]

(Original post by Ataraxian-Walker)
What are the ethical and social issues of genetic screening? :/

NEVER EVER mention playing God or designer babies because those answers are fit for Religious Studies and not a science paper.

You can mention the fact that other conditions may be discovered which may cause lifelong trauma or expense to cure treatment at an earlier stage or the fact that false results may be attained.

[avipsita]

for this paper i am sure some enzyme questions and lots of diffusion and heart especially heart questions might come up

[Ataraxian-Walker]

(Original post by verdikt)
NEVER EVER mention playing God or designer babies because those answers are fit for Religious Studies and not a science paper.

You can mention the fact that other conditions may be discovered which may cause lifelong trauma or expense to cure treatment at an earlier stage or the fact that false results may be attained.

Thanks (: