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OCR Biology F212 (Molecules, Biodiversity, Food and Health)- 21st May 2012

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Reply 380
Original post by Harriet : )
Anyone who want to revise biodiversity questions? - Really struggling with adaptation and variation :frown:


Yup I would love to.
Original post by Salmonidae
You mean here?


Hmm, don't think so. The school's computer isn't letting me download those but I'm talking about the Google docs thing. Thanks for helping :smile: Don't worry - I'm on to history revision now and will wait til I get home.
Reply 382
can anyone say me how intake to more saturated fat decreases the number of receptors on the cells and increase the cholesterol level?
Original post by Kalliope
Hmm, don't think so. The school's computer isn't letting me download those but I'm talking about the Google docs thing. Thanks for helping :smile: Don't worry - I'm on to history revision now and will wait til I get home.


https://docs.google.com/leaf?id=0By84nmCmJZnWQkdFTmd5bGUydDQ&sort=name&layout=list&pid=0By84nmCmJZnWMU5EN2RDcmtBU2s&cindex=1 is this what you were looking for? :tongue:
Original post by AS01
Yup I would love to.


Excellent- want to go first? :smile:
Reply 385
Original post by Harriet : )
Excellent- want to go first? :smile:


ok. Describe the characteristic of continuous variation. (3)
Reply 387
Original post by AS01
ok. Describe the characteristic of continuous variation. (3)


quantitative
no distinct groups
intermediate values
Reply 388
Does anyone think ex situ will come up again????????????????
Reply 389
Original post by narli
quantitative
no distinct groups
intermediate values


I would give you 2 marks. Better to say contain range of values between two extremes. Ya quantitative and also affected by environmental factors.
Reply 390
Original post by narli
Does anyone think ex situ will come up again????????????????


I would not want to predict just know all of the stuff in the book. As you can see on most of the papers they have asked about ex situ. Might be in terms of seed banks or captive breeding.
What actually causes the damage to the epithelial of the artery wall to allow the plaque to deposit?
Original post by Future_Dr
What actually causes the damage to the epithelial of the artery wall to allow the plaque to deposit?


Firstly, it's the endothelium, not epithelial, and that damage is cause by carbon monoxide and by high blood pressure.

Secondly, plaque isn't deposited. Cholesterol and LDL's are what are deposited, forming an atheroma. A plaque is only when the atheroma breaks through the endothelium lining and sticks out into the lumen of the artery.
Original post by Future_Dr
What actually causes the damage to the epithelial of the artery wall to allow the plaque to deposit?


High blood pressure often caused by a high salt diet
Does angina, mycocardial infarction and cardiac arrest and conary thrombosis all come under Coronary Heart Disease?
Original post by Future_Dr
Does angina, mycocardial infarction and cardiac arrest and conary thrombosis all come under Coronary Heart Disease?


Yes, although it's worth bearing in mind that coronary thrombosis and mycocardial infarction lead to cardiac arrest, not the other way around.
Original post by Unsworth
Firstly, it's the endothelium, not epithelial, and that damage is cause by carbon monoxide and by high blood pressure.

Secondly, plaque isn't deposited. Cholesterol and LDL's are what are deposited, forming an atheroma. A plaque is only when the atheroma breaks through the endothelium lining and sticks out into the lumen of the artery.


Can you please tell me in detail what is a plaque, atheroma, and athermateous plaque. Sorry but it doesn't really state the differences in my notes so I assumes that they were the same. Also I thought that Cholestrol were due to the LDLs as they were carried that way. Do you get LDLs and Cholestrol seperate?
(edited 11 years ago)
Hoping these topics come up:
Nucleic acids
Haemoglobin vs collagen
Artifical selection
Immune system
Smoking
And any of the easy stuff from biodiversity lol :P
Original post by Future_Dr
Can you please tell me in detail what is a plaque, atheroma, and athermateous plaque. Sorry but it doesn't really state the differences so I assumes that they were the same.


Ok, so an atheroma is basically the deposits of fatty substances, cholesterol, low density lipoproteins, dead cells, platelets and fibres.

An atheroma is caused by atherosclerosis. This is happens by carbon monoxide and/or high blood pressure causing damage to the endothelium (inner lining) of the artery. This damage to the artery encourages the deposition of those fatty substances, cholesterol, LDL's etc.

The continuous build up of these deposits under the endothelium of the artery may cause the atheroma to build up and stick out, into the lumen of the artery - this is called a plaque.

A plaque further reduces blood flow, as the lumen is smaller, so blood pressure increases further. The membrane which covers the plaque can get damaged due to the high blood pressure, this leaves the fatty deposits exposed. Nicotine in cigarette smoke causes the platelets and red blood cells in the blood to become more sticky, and so these can get can stuck to the exposed fatty deposits on the plaque. This is called thrombosis.

Thrombosis can also lead to a thrombus (a blood clot) which can be broken off and clog a narrower artery, which will stop blood flow to that artery and may lead to a stroke.

I have never heard of an athermateous plaque before though, so I can't help you there, I doubt you need to know what it is either.

Hope that helped a bit!
Original post by Future_Dr
Can you please tell me in detail what is a plaque, atheroma, and athermateous plaque. Sorry but it doesn't really state the differences in my notes so I assumes that they were the same. Also I thought that Cholestrol were due to the LDLs as they were carried that way. Do you get LDLs and Cholestrol seperate?


They all do mean the same thing I believe, and they lead to the condition Artheriosclerosis.

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