AQA BIOL5 ~ 17th June 2013 ~ A2 Biology

My Oestrous cycle poster

It was GCSE yeah. If I were you I'd learn it but only in a small amount of detail, pretty much what the original person said, as you'd be surprised how many times you can link it in
(negative feedback, substances across membranes, hormonal control, you could even mention it in one about disease as damage can cause diabetes insipidus)

Can anyone give me any advice on the 25 mark essay, i keep getting 12/13 in practise papers, what is the structure? what should i be writing about?

Probably not :/
But remember thats all only worth 25% of the paper so if you dont get it all done in those 3 days it's not the end of the world

What really?! Do the legacy papers and latest papers take ages to do?!!! You've scared me now!! how many past papers have you done and how long did they take you? What if I spent 3 days just on all the old and new past papers? Would that me enough time?

The best advice is to stop seeking advice like this because we don't know how you study. Stop worrying and open your books. Sorry if it's harsh.

~How does insulin bring about an increase in the number of carrier molecules in the cell surface membrane?

Before anyone panics this is from my essay revision, not unit 5

Insulin has its own second messenger system, which is different to Glucagon/adrenaline

1. Insulin binds to glycoprotein receptors embedded in the plasma membrane.
2. The hormone-receptor complex activates an Insulin-Receptor Substrate (IRS) inside the cell which acts as the second messenger molecule.
3. The IRS complex stimulates the Golgi apparatus to bud off vesicles containing glucose carrier proteins.
4. The vesicles fuse with the plasma membrane, increasing the number of glucose carriers on the membrane (and increasing the permeability of the membrane to glucose molecules).
5. The IRS complex also activates the glycogen synthase enzymes which stimulate glycogenesis. The IRS complex stimulates one enzyme, which in turn stimulates another. One IRS complex can stimulate many enzymes, due to the cascade effect.

Before anyone panics this is from my essay revision, not unit 5

Insulin has its own second messenger system, which is different to Glucagon/adrenaline

1. Insulin binds to glycoprotein receptors embedded in the plasma membrane.
2. The hormone-receptor complex activates an Insulin-Receptor Substrate (IRS) inside the cell which acts as the second messenger molecule.
3. The IRS complex stimulates the Golgi apparatus to bud off vesicles containing glucose carrier proteins.
4. The vesicles fuse with the plasma membrane, increasing the number of glucose carriers on the membrane (and increasing the permeability of the membrane to glucose molecules).
5. The IRS complex also activates the glycogen synthase enzymes which stimulate glycogenesis. The IRS complex stimulates one enzyme, which in turn stimulates another. One IRS complex can stimulate many enzymes, due to the cascade effect.

Can someone please link me the thread to the essay practice. Thanks