Turn on thread page Beta
    • Thread Starter
    Offline

    0
    ReputationRep:
    ok here goes if you can help

    1) oxidative phosphorylation - is this basically the process if the electron transport chain?

    2) in anaerobic respiration ( muscles ) pyruvate is converted to lactic acid do i need to know the intermediate steps?

    3) in anerobic respiration ( both muscle and yeast ) what is the ATP yeild?

    4) can anyone explain osmoregulation and nitrogenous excretion in the mammalian kidney please!!

    I HATE the kidney ( and would get rid of it had it not been needed :P )
    Offline

    2
    ReputationRep:
    1) i believe so

    2) i think you just need to know that pyruvate itself acts as the hydrogen acceptor, freeing NADred, and allowing glycolysis to continue.

    3) net gain of 2 molecules per glucose i have read somewhere

    4) proteins cannot be stored in the body, so they are broken down and deanimated in the liver (removal of the NH2 group) and reacts with CO2 to produce urea in a process called the ornithine cycle. Urea is less toxic than NH3 and CO2 in the body. This urea is removed from the blood via ultrafiltraion and removed by the kidney into the urethra to the outside world. Some urea is reabsorbed in the PCT.

    Oh gosh, osmoregulation. I'd like to help, but that would take all day. I suppose you have to remember that ADH is released by the posterior lobe of the pituitary gland to help the collecting ducts reabsorb water from filtrate via osmosis. It does this by combining to some molecule in the cell wall, and thats as far as i can remember. Oh, and negative feedback allows secretion of ADH to cease.
    Offline

    2
    ReputationRep:
    (Original post by rainjan_4now)
    Oh gosh, osmoregulation. I'd like to help, but that would take all day. I suppose you have to remember that ADH is released by the posterior lobe of the pituitary gland to help the collecting ducts reabsorb water from filtrate via osmosis. It does this by combining to some molecule in the cell wall, and thats as far as i can remember. Oh, and negative feedback allows secretion of ADH to cease.
    I think it combines with a protein molecule called an "aquaporin", and this increases the permeability of the collecting duct to allow more water to move my osmosis out of the filtrate and into the bloodstream again...

    And osmoreceptors in the ...hypothalamus ( ? ) allow the regulation/ internal monitoring of the water content of the body, which sends the message to the pituitary gland to produce/ cease production of ADH.

    Hope that helps!
    • Thread Starter
    Offline

    0
    ReputationRep:
    so basically osmoregulation is the maintainin of a constant salt concentration in our body fluids so that osmosis does not occur and mess up our cells?

    and this is achieved by osmoreceptoors (?) in the collecting duct (?) which send messages to the pituitary gland releasing ADH or not so more or less water is collected?
    Offline

    2
    ReputationRep:
    (Original post by Synkronized)
    I think it combines with a protein molecule called an "aquaporin", and this increases the permeability of the collecting duct to allow more water to move my osmosis out of the filtrate and into the bloodstream again...

    And osmoreceptors in the ...hypothalamus ( ? ) allow the regulation/ internal monitoring of the water content of the body, which sends the message to the pituitary gland to produce/ cease production of ADH.

    Hope that helps!
    It does, it does!! I read the latter part last week, and i'm now remembering it. The first part i have read, but it didnt stick in my mind due to the subject being so darn crappy!!!!
    Offline

    2
    ReputationRep:
    Osmoreceptors are in the hypothalamus.
    • Thread Starter
    Offline

    0
    ReputationRep:
    so how does it know to release ADH or not ?!?!

    im a thicky today lol
    Offline

    2
    ReputationRep:
    (Original post by rainjan_4now)
    It does, it does!! I read the latter part last week, and i'm now remembering it. The first part i have read, but it didnt stick in my mind due to the subject being so darn crappy!!!!
    WOOHOO! I actually got something right in biology

    Why is there so much bio to learn for unit 5/6? They could ask ANYTHING
    Offline

    2
    ReputationRep:
    Basically the receptors are the osmoreceptors which are in the hypothalamus in the pituitary gland.
    And when water concent is too low, they're stimulated and ADH is released.
    And then it causes stuff to happen in the walls of the collecting duct.. I dunno how much you need to know but on OCR we need to know all the stuff in the collecting duct (the vesicles with channels, fuse, water retained etc!)
    Offline

    2
    ReputationRep:
    (Original post by Synkronized)
    WOOHOO! I actually got something right in biology

    Why is there so much bio to learn for unit 5/6? They could ask ANYTHING
    I'm sure if you look around this website, you'll see that many people share a disliking for biology, esp central concepts (OCR). I have no idea why the exam board would do this to us. The unit is toooooooo big, and its bugging me because i am waaaaaay weaker in certain areas than others, but because the unit is large, i not only have to revise my weak areas, i also have to re-revise the areas i'm comfortable with so they do not escape my mind.

    DAMN YOU OCR :mad:
    • Thread Starter
    Offline

    0
    ReputationRep:
    so much to learn for 5 and 6?!

    4 is a huge section!! its MASSIVE ive been studying weeks and feel like i havnt even dented it, im not bothered bout 5 at all - whats that genetic stuff and evolution?

    6 is everything so by learning 4 and 5 ive only got 1 2 and 3 left lol
    Offline

    2
    ReputationRep:
    (Original post by violet)
    but on OCR we need to know all the stuff in the collecting duct (the vesicles with channels, fuse, water retained etc!)
    thats me failed already then, unless i can revise and remember it in two days- or pray for it not to come up

    I need to get off the computer but i cant.....help!
    Offline

    2
    ReputationRep:
    (Original post by rainjan_4now)
    I'm sure if you look around this website, you'll see that many people share a disliking for biology, esp central concepts (OCR). I have no idea why the exam board would do this to us. The unit is toooooooo big, and its bugging me because i am waaaaaay weaker in certain areas than others, but because the unit is large, i not only have to revise my weak areas, i also have to re-revise the areas i'm comfortable with so they do not escape my mind.

    DAMN YOU OCR :mad:
    I know.... I still have to revise AS for the synoptic :eek:
    And I have a maths exam tomorrow....................... HMM!!
    CC is too big, when I learn something new, I forget the thing I learnt the day before!
    Offline

    2
    ReputationRep:
    (Original post by rainjan_4now)
    thats me failed already then, unless i can revise and remember it in two days- or pray for it not to come up

    I need to get off the computer but i cant.....help!
    It's probably not gonna come up.. Cos there was an essay question on it on the Jan 05 paper.. But then again this is OCR we're talking about so it might come up again :eek:
    Just learn the mark scheme answer from Jan 05, instead of like 3 pages in the book!
    Offline

    2
    ReputationRep:
    4 is a huge section!! its MASSIVE ive been studying weeks and feel like i havnt even dented it, im not bothered bout 5 at all - whats that genetic stuff and evolution?
    unless i can revise and remember it in two days- or pray for it not to come up
    I'm doing Edexcels synoptic papers. Genetics went in so much easier then evolution/biodiversity, im gonna have to blitz that tomorrow. And believe me, praying is ALWAYS good for a bio exam, and you'd be suprised how much you can cram in a day. Also, look through a question/answer part of a txtbook right before the exam: everytime i've done that i've ALWAYS seen a question that comes up 5 mins later in the exam, its like legal cheating
    Offline

    13
    ReputationRep:
    Lol, I love it when that happens. You just sit there and smugly grin!
    • Thread Starter
    Offline

    0
    ReputationRep:
    hehe that happened in my physics jan unit 4 paper - the question of the expanding universe

    I just hope that they dont ask to many Qs on the nervous system and the bainbridge reflex etc cause im a little rough round the edges on all that. I studied human geo so im totally neglected that part of the bio sylybus and hopin it wont make much differance
    Offline

    2
    ReputationRep:
    (Original post by purplecrayon)
    I just hope that they dont ask to many Qs on the nervous system and the bainbridge reflex etc cause im a little rough round the edges on all that.
    BAINBRIDGE REFLEX?!

    You know that horrible feeling when you see a question in the exam that you haven't revised, infact you totally forgot it even existed, and then the key word jogs something in your memory that says "oh yeah, we did that 2 years ago, don't remember what it is" ?

    Thats what i just got. Back to the text book. sigh.

    :p:
    Offline

    2
    ReputationRep:
    (Original post by Synkronized)
    BAINBRIDGE REFLEX?!

    You know that horrible feeling when you see a question in the exam that you haven't revised, infact you totally forgot it even existed, and then the key word jogs something in your memory that says "oh yeah, we did that 2 years ago, don't remember what it is" ?

    Thats what i just got. Back to the text book. sigh.

    :p:
    Please tell me that you two are talking about physics.............. :frown:
    • Thread Starter
    Offline

    0
    ReputationRep:
    lol yeah i know that feeling and i tend to just guess

    http://www.nelsonthornes.com/seconda...uide/4/4_1.htm

    that is a very good website for the edexcel sylybus - but you could make it work for any sylybus too!
 
 
 
Turn on thread page Beta
Updated: June 19, 2005
The home of Results and Clearing

1,638

people online now

1,567,000

students helped last year

University open days

  1. Sheffield Hallam University
    City Campus Undergraduate
    Tue, 21 Aug '18
  2. Bournemouth University
    Clearing Open Day Undergraduate
    Wed, 22 Aug '18
  3. University of Buckingham
    Postgraduate Open Evening Postgraduate
    Thu, 23 Aug '18
Poll
A-level students - how do you feel about your results?

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

Write a reply...
Reply
Hide
Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.