Edexcel A2 Biology Unit 5 (6BIO5) - 22/06/2011- OFFICIAL THREAD !

two types Pf and Pfr.
Pf absorbs red light and is converted into pfr
pfr absorbs far red light and forms pr

in long winters-plenty of darkness so large amount of pfr is converted into pr
summer not enough time nor darkness for pfr to be convereted into pf as not nuf of far red light is absorbed due to lack of darkness

long day plnts only flower when the exceed critical value and when the have a period of darkness less than 12 hours
so these pfr so less than 12 means less darkness so more red light so more pfr converted into pfr stimulate flowering

short day plnts
only flowe when the have more than 12 hours of darkness so these need pf so by having more darkness more pfr absorbs far red light and forms pf which is used for flowering

rushed kinda revisin article

What are you revising for the article?

im acutally revisin key concept gene therapy, epo, ifg-1, etc etc
im actually revising answers to questions that may come up. from there onwards linking certain aspects of the article becomes much more easier.

i'm sure in previsous posts there are word documents about the articlle.

IGF-1 is a protein made in the liver stimulated by the human growth hormone and it is used for cell growth particularly in the muscles. Used to increase size, strenght and effieiceny of muslces.
exist in five forms- MGF.
These forms are made as result of splicing mrna transcibed from dna- this pre mrna. this contains sections introns that dnt code for proteins these are removed. however some exons are also removed that code for mrna slightly differently from the original MRNA, so different amino acids, producin variations of IGF-1 protein.

CT:
-uses X-rays
-produces cross-section images of the brain
-different densities of tissue absorb different amounts of radiation and show up as different colours
-shows major structures in the brain without much detail
-used to tell the extent of an abnormality and its location in the brain
-loss of a function may be associated with the abnormality seen

MRI:
-uses radio waves
-cross-section images
-tissues seen in much more detail
-extent of abnormality and location
-loss of a function may be associated with the abnormality seen

fMRI:
-like MRI but show changes in brain activity as they happen
-more oxygenated blood flows to active brain areas, these areas show up in a different colour
-identify parts of the brain associated with a function whilst it is performed in the scanner
-study diseases caused by abnormal brain activity rather than structure


CGP

What do we need to know about critical window. nature and nuture and Habituation(I know already)? The green book ann fullick just talk rubbish about it and the CGP dont mention anything about it.

What do we need to know about critical window. nature and nuture and Habituation(I know already)? The green book ann fullick just talk rubbish about it and the CGP dont mention anything about it.

there's quite alot about those 3 things in the CGP book...

yeah the CGP book does those quite well. Haven't looked at it for habituation but the nature-nurture debate and critical window stuff was done very nicely.

yup and habituation is summarised very well and the core practical is done in bullet points which is always good!

The main areas where I expect they'll bring up AS/unit 4 knowledge will be related to the scientific article, like the heart and things we learnt in unit 1, probably not in much detail, but quickly looking at the heart structure and a couple of other things like blood clotting, probably wouldn't hurt. As transcription factors comes up briefly in this topic, maybe also look back at that?

Methods of co-ordination, I think they're most likely to ask for differences between nervous system/ hormones in humans and plant growth factors. e.g.
- nervous response is faster because it uses electrical impulses but more localised
- hormones are a chemical response so slower as they travel in blood, but its more widespread throughout the body.
- plant growth factors are also chemical, but because plants don't have a circulatory system carrying blood, the chemicals (IAA etc.) move by diffusion, so the response is more localised to the area near where they are released.

Finally the ridiculous ethics stuff- you can probably make it up, but what they want are comments about insurance companies getting peoples genome and unfairly discriminating, and drug companies creating drugs for specific genetic variations, which will increase costs and mean that only rich people can afford it.

I'm not 100% about all of this but that's my best guess, hope it helps