Year 12s: what will be the first way you research your future options? >>

A2 Biology OCR June 2015 Revision Thread

Scroll to see replies

Hey guys how do u revise for F215 I've tried so many methods but nothing seems to sink in please help

Posted from TSR Mobile

Write notes, try practice questions, cry over questions, reread notes when I get something wrong, repeat.

Reply 661

acd55

This might sound stupid I think I might be reading the question wrong but in jan 2011 paper for f214, q1 why is the hydrogen acceptor after glycolysis
pyruvate for mammal and ethanal for yeast?

Posted from TSR Mobile

Reply 662

ChoccyPhilly

Original post by hpcp

I've done that question, you're right :smile:

Reply 663

acd55

Original post by ChoccyPhilly

I've done that question, you're right :smile:

I don't get the answer, not really sure why I don't :tongue:

Isn't pyruvate reduced to ethanal first?
Sorry if it doesn't take too long could you explain it briefly, thank you! :smile:

Posted from TSR Mobile

Reply 664

Kirxn12

Okay I'll try that seems like a good method to help memorise the content thanks

Posted from TSR Mobile

Reply 665

AnnekaChan173

Original post by hpcp

Oooo this has updated.

For the cycle to repeat so we can continue respiring anaerobically, we need to reform NAD+ (So it can pick up the Hs in Glycolysis), and we do that by transferring the H onto the substrate (pyruvate or ethanal)

Reply 666

ChoccyPhilly

Original post by hpcp

I don't get the answer, not really sure why I don't :tongue:

Isn't pyruvate reduced to ethanal first?
Sorry if it doesn't take too long could you explain it briefly, thank you! :smile:

Posted from TSR Mobile

In humans, pyruvate turns directly into lactate and is reduced.

I think you're confusing this by the breakdown of alcohol in the liver, which does turn into ethanal at some point, I believe

Reply 667

TheLegalDealer

Anyone know a simple method to calculate expected value in chi squared ?

Reply 668

AnnekaChan173

Original post by ChoccyPhilly

In humans, pyruvate turns directly into lactate and is reduced.

I think you're confusing this by the breakdown of alcohol in the liver, which does turn into ethanal at some point, I believe

Anaerobic respiration of yeast is different - decarboxylation, then reducing the ethanal to ethanol.

Original post by TheLegalDealer

Anyone know a simple method to calculate expected value in chi squared ?

You'll have to give an example.

(edited 8 years ago)

Reply 669

ChoccyPhilly

The **** is glucocorticoids? Randomly popped up on a past paper and I've never seen that word before

Reply 670

Yua

Original post by ChoccyPhilly

The **** is glucocorticoids? Randomly popped up on a past paper and I've never seen that word before

stuff like cortisol which is secreted from the cortex is all i know about it

Reply 671

ChoccyPhilly

Original post by Yua

stuff like cortisol which is secreted from the cortex is all i know about it

Thanks. All the knowledge gaps are frustrating, especially when the exam asks for 5% of obscure content within the book

Reply 672

TheLegalDealer

Original post by AnnekaChan173

Anaerobic respiration of yeast is different - decarboxylation, then reducing the ethanal to ethanol.

You'll have to give an example.

The ratio is 1:2:1

chisquared.png5.3KB

Reply 673

TheLegalDealer

Original post by Yua

stuff like cortisol which is secreted from the cortex is all i know about it

They're basically steroid hormones produced in the cortex of the kidney examples include mineralcorticoids which control Na+/K+ levels in blood as well the usual steroid hormone e.g. tetosterone .

This isn't explicitly stated in the spec but I have seen Q's on them but they dont ask for answers outside spec