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AQA BIOL1 Biology Unit 1 Exam - 16th May 2011

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Reply 680
Original post by Jubilee~
Okay so here's a question.


Explain how the Cholera bacteria causes diarrhea in the patients
- mention water potential etc.


Vibrio Cholera has a flagelum that pentrates its way through the epithelial cells of the small intestine causing the ion channels to open so the chloride ions in the epithelial cells flood in to the lumen of the small intestine, reducing the water potential in the lumen and increasing the water potential in the epithelail cell. water then goes from high to low water potential via osmosis.
Reply 681
Original post by Rickesh
Cholera causes the chloride ion channels to open in the eptihelial cells of the small intestines. The chloride ions then move out of the cells into the lumen, lowering the water potenial of the lumen. Water therefore follows out of the blood into the lume from a high water potential to low, by osmosis


Great answer but be careful, the water moves flows from the CELLS (higher water potential) into the lumen (lower water potential) on this water potential gradient by osmosis.
Original post by ??????????????????

Original post by ??????????????????
2 moles of wood.


Lol perfect answer
Original post by Rickesh

Original post by Rickesh
what is cardiac output mean ?


Amount of blood pumped by the heart in a minute?
Reply 684
Original post by ??????????????????
My fave.

Cholera produces a toxin that binds to the channel proteins for Cl- ions. This causes them to open. The Cl ions will enter the small intestine lumen lowering the water potential. This causes water to enter through osmosis so the faeces become watery. Symptons include diarrhea and flatulance.

Can anybody tell me which processes use channel proteins and which use carrier proteins?


Carrier proteins for active transport and Channel proteins for faciliatated diffusion
Original post by Jubilee~

Original post by Jubilee~
Great answer but be careful, the water moves flows from the CELLS (higher water potential) into the lumen (lower water potential) on this water potential gradient by osmosis.


Actually water flows from the BLOOD to the lumen through the epithelium cell
Reply 686
Original post by ??????????????????
I can't remember the questions and feeling tired so :/ must put JPOP louder to keep awake.
1. I think it is to establish whether or not the drug is attatching to the antigen.
2. The first antibody binds to the antigen if it is present. The second binds to the first antibody. Used to see if it binds.
3. The antibodies are still there. The solution is not I think.
4. The enzyme is a monoclonal antibody and is complimentry in shape to the antibody not antigen.


I get it now thank you :smile: I've struggled with that beastly question for two years :P
I'm so tired the question marks in my username appear to be moving...
Time for my skittles hit!
Reply 688
Original post by Rizzy J
Vibrio Cholera has a flagelum that pentrates its way through the epithelial cells of the small intestine causing the ion channels to open so the chloride ions in the epithelial cells flood in to the lumen of the small intestine, reducing the water potential in the lumen and increasing the water potential in the epithelail cell. water then goes from high to low water potential via osmosis.


great, just with the last bit make sure you specify that the water moves from the epethilial cell into the lumen.
just so you dont lose any marks :smile:
Reply 689
Original post by BeejTheone
Amount of blood pumped by the heart in a minute?


I think so because stroke volume is volume of blood in the something lol? and the heart rate is the number of beats in a minute i think ??
Original post by Tericon
I get it now thank you :smile: I've struggled with that beastly question for two years :P


Retaking is for the third time? Third time lucky? :O Though need to be first time lucky for me :frown: Hardly any unis like retakes when applying for medicene. :frown:
Original post by Rickesh

Original post by Rickesh
I think so because stroke volume is volume of blood in the something lol? and the heart rate is the number of beats in a minute i think ??


Yeah i just checked what i said is right.

Stroke volume is volume of blood pumped by the ventricles in a heartbeat lol ;D

Im off now! Gl everyone :smile:
(edited 12 years ago)
Reply 692
Original post by ??????????????????
Retaking is for the third time? Third time lucky? :O Though need to be first time lucky for me :frown: Hardly any unis like retakes when applying for medicene. :frown:


What did you get the other times ? Wow your applying for medicine ? Already applied or going to ?
Reply 693
How does TB spread and what are the effects of TB ?
Reply 694
Original post by BeejTheone
Actually water flows from the BLOOD to the lumen through the epithelium cell


:confused:
just checked my revision guide and it says
'loss of cl ions from the epethelial cells raises their water potential, while increase of chloride ions in the lumen of the intestine lowers its water potential. Water flows from the cells into the lumen. Loss of ions from the epethelial causes ions to move by diffusion into the epethelial cells from surrounding BLOOD. This causes water to move by osmosis from the blood into the intestine'

so what i meant is that water first moves from epethelial into the lumen, then from blood into the epethelial if that makes sense...
got 49/60 on the january 2010 paper which is 100 ums with the grade boundaries then. Funny how i got caught out on questions i advised people on this forum to watch out for :P
Original post by Rickesh
what is cardiac output mean ?


What does*. :smile:
Reply 697
Original post by Jubilee~
:confused:
just checked my revision guide and it says
'loss of cl ions from the epethelial cells raises their water potential, while increase of chloride ions in the lumen of the intestine lowers its water potential. Water flows from the cells into the lumen. Loss of ions from the epethelial causes ions to move by diffusion into the epethelial cells from surrounding BLOOD. This causes water to move by osmosis from the blood into the intestine'

so what i meant is that water first moves from epethelial into the lumen, then from blood into the epethelial if that makes sense...


So what i said was right?
Original post by Rickesh
What did you get the other times ? Wow your applying for medicine ? Already applied or going to ?


No I'm taking my first sitting. Asked if she was lol
Doubt I will get in anyway. Haven't applied. Shall get my as results. If good then do UKCAT. If not then do something else not sure on. If UKCAT and AS are good (doubt it) then I shall apply. Got a ton of work experience and learnt from it so better be worth it :angry:
Reply 699
Original post by Sighrawr
What does*. :smile:


yeah lol realised that after I sent it !

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