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As biology unit 1 21/5/2014 panic thread

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Original post by ThatMadClown
sorry my bad, I'm doing the AQA spec, the thread wasn't aimed towards a specific exam board so I thought it would be AQA, regardless, how's revision coming along, my bio exams on wednesday..


Oh haha! I literally almost had a myocardial infarction haha :wink:
I think AQA is the most popular board anyway, and the thread really wasn't that clear!
Ha! I've given up on biology revision. I really don't like it at all :frown: I just banged out bio revision in the easter so I wouldn't have to look at it again until exam time :')
Yeah mine too! I want it to be overrrr.
How's revision going for you? :smile:
Lol yeah I get what you mean, my exams finish on the 9th of june (doing AS level) D:
just really can't be bothered anymore, especially with bio because theres so much to memorise... it's like, theres no need for the book to be that big and the exams are even worse :P
what causes myocardial infarction? (just seeing whether you know your stuff) :wink:
Original post by Me123456789
Are you in the UK? Is thread for the UK exam or the international one?

nope ,I'm from Oman doing IAL
Reply 63
Avatar for HQazi
HQazi
9
Original post by Paras Agarwal
sure.. first of all we have to understand what causes it to be sticky.. and thats because water doesnt move out from the epithelial cells into mucus... now why?
first of all the CFTR channel doesn't open hence the chloride ions do NOT move out.. the Na+ ions do not move out because there is no chloride ions to balance the charge to form (NaCl) as a result the water potential is into the cell so the inside of the cell is hypertonic..so water is drawn into the cell by osmosis.. this means the mucus (obv outside the cell) will now be sticky.. :smile: hope you understand


Ahh. Thanks so much.
Original post by HQazi
Ahh. Thanks so much.


no problem :smile:
images.jpg:cool: :biggrin:
Original post by ThatMadClown
Lol yeah I get what you mean, my exams finish on the 9th of june (doing AS level) D:
just really can't be bothered anymore, especially with bio because theres so much to memorise... it's like, theres no need for the book to be that big and the exams are even worse :P
what causes myocardial infarction? (just seeing whether you know your stuff) :wink:


When the coronary arteries that supply oxygenated blood to the heart muscle get blocked or restricted,


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Original post by Blob :)
When the coronary arteries that supply oxygenated blood to the heart muscle get blocked or restricted,


Posted from TSR Mobile


which means less oxygen gets to the heart muscle so there is less respiration which leads to myocardial infarction
Original post by ThatMadClown
which means less oxygen gets to the heart muscle so there is less respiration which leads to myocardial infarction


NOT less .. there will be NO oxygen because mycoardial infarction is a COMPLETE blockage of the artery :smile: hence no oxygen reaches the cardiac muscles so no energy produced for the contraction and relaxation of the heart muscles so anaerobic respiration occurs leading to the buildup of lactic acid which lowers pH hence killing the cardiac tissues
Original post by Paras Agarwal
NOT less .. there will be NO oxygen because mycoardial infarction is a COMPLETE blockage of the artery :smile: hence no oxygen reaches the cardiac muscles so no energy produced for the contraction and relaxation of the heart muscles so anaerobic respiration occurs leading to the buildup of lactic acid which lowers pH hence killing the cardiac tissues


I'm doing the AQA spec, mark scheme says otherwise on that nonetheless, good to see you know your stuff :cool:
Original post by ThatMadClown
I'm doing the AQA spec, mark scheme says otherwise on that nonetheless, good to see you know your stuff :cool:


thanks mate! :biggrin:
Reply 71
Avatar for N.Choi
N.Choi
2
If anyone wants a small test.... describe the structure of the arteries and veins and explain how it relates to their function.
Could someone please explain how co-transport works
Original post by N.Choi
If anyone wants a small test.... describe the structure of the arteries and veins and explain how it relates to their function.


not too bothered to write how it relates to its functions but

Arteries: flow from heart, thick elastic muscle layer, no valves, oxygenated

Veins: flow to heart, thin elastic muscle layer, has valves, deoxygenated
Original post by N.Choi
If anyone wants a small test.... describe the structure of the arteries and veins and explain how it relates to their function.


okay so here goes:
ARTERIES
1) They have thick muscular wall to withstand the high blood pressure
2) They have smooth muscle to alter diameter of lumen to vary blood flow
3) elastic fibres- allow walls to stretch when blood is pumped into the artery and then recoil smoothing the blood flow
4) lined with a smooth layer of endothelial cells- low friction surface to ease blood flow

VEINS
1) They have thin wall because blood is flowing under low pressure
2) They have little smooth muscle and elastic fibres because there is no pulse of blood so no stretching and recoiling
3) endothelial cells again to ease blood flow as it is a low friction surface
4) Valves to prevent backflow

YUPP THATS IT :smile:
(edited 9 years ago)
Original post by thanbirh
Could someone please explain how co-transport works


99.9999% sure its not in the edexcel IAL syllabus :smile:
Reply 76
Avatar for hiya123
hiya123
Can somebody explain why the blood pressure in the arteries fluctuates please:smile:
Could someone refer to me where i could download a pdf version of the Edexcel AS biology revision guide?
I need it too!

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Can't find the revision guide anywhere online :/ try asking your bio teacher ?

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